Table des matières
Last updated on: 2020/01/30 03:28
Help and Documentation
Help on external commands
External commands are binary executables or scripts generally found in /bin, /sbin, /usr/bin ou /usr/sbin :
root@debian8:~# type ifconfig ifconfig is /sbin/ifconfig
root@ubuntu1604:~# type ifconfig ifconfig is /sbin/ifconfig
[root@centos7 ~]# type ifconfig ifconfig is /sbin/ifconfig
SLES12SP1:~ # type ifconfig ifconfig is /sbin/ifconfig
Help for an external command can generally be obtained by using the –help option with the command in question :
root@debian8:~# du --help | more Usage: du [OPTION]... [FILE]... or: du [OPTION]... --files0-from=F Summarize disk usage of each FILE, recursively for directories. Mandatory arguments to long options are mandatory for short options too. -0, --null end each output line with NUL, not newline -a, --all write counts for all files, not just directories --apparent-size print apparent sizes, rather than disk usage; although the apparent size is usually smaller, it may be larger due to holes in ('sparse') files, internal fragmentation, indirect blocks, and the like -B, --block-size=SIZE scale sizes by SIZE before printing them; e.g., '-BM' prints sizes in units of 1,048,576 bytes; see SIZE format below -b, --bytes equivalent to '--apparent-size --block-size=1' -c, --total produce a grand total -D, --dereference-args dereference only symlinks that are listed on the command line -d, --max-depth=N print the total for a directory (or file, with --all) only if it is N or fewer levels below the command line argument; --max-depth=0 is the same as --summarize --files0-from=F summarize disk usage of the --More--
root@ubuntu1604:~# du --help | more Usage: du [OPTION]... [FILE]... or: du [OPTION]... --files0-from=F Summarize disk usage of the set of FILEs, recursively for directories. Mandatory arguments to long options are mandatory for short options too. -0, --null end each output line with NUL, not newline -a, --all write counts for all files, not just directories --apparent-size print apparent sizes, rather than disk usage; although the apparent size is usually smaller, it may be larger due to holes in ('sparse') files, internal fragmentation, indirect blocks, and the like -B, --block-size=SIZE scale sizes by SIZE before printing them; e.g., '-BM' prints sizes in units of 1,048,576 bytes; see SIZE format below -b, --bytes equivalent to '--apparent-size --block-size=1' -c, --total produce a grand total -D, --dereference-args dereference only symlinks that are listed on the command line -d, --max-depth=N print the total for a directory (or file, with --all) only if it is N or fewer levels below the command line argument; --max-depth=0 is the same as --summarize --files0-from=F summarize disk usage of the --More--
[root@centos7 ~]# du --help | more Usage: du [OPTION]... [FILE]... or: du [OPTION]... --files0-from=F Summarize disk usage of each FILE, recursively for directories. Mandatory arguments to long options are mandatory for short options too. -0, --null end each output line with 0 byte rather than newline -a, --all write counts for all files, not just directories --apparent-size print apparent sizes, rather than disk usage; although the apparent size is usually smaller, it may be larger due to holes in ('sparse') files, internal fragmentation, indirect blocks, and the like -B, --block-size=SIZE scale sizes by SIZE before printing them; e.g., '-BM' prints sizes in units of 1,048,576 bytes; see SIZE format below -b, --bytes equivalent to '--apparent-size --block-size=1' -c, --total produce a grand total -D, --dereference-args dereference only symlinks that are listed on the command line -d, --max-depth=N print the total for a directory (or file, with --all) only if it is N or fewer levels below the command line argument; --max-depth=0 is the same as --summarize --files0-from=F summarize disk usage of the --More--
SLES12SP1:~ # du --help | more Usage: du [OPTION]... [FILE]... or: du [OPTION]... --files0-from=F Summarize disk usage of each FILE, recursively for directories. Mandatory arguments to long options are mandatory for short options too. -0, --null end each output line with 0 byte rather than newline -a, --all write counts for all files, not just directories --apparent-size print apparent sizes, rather than disk usage; although the apparent size is usually smaller, it may be larger due to holes in ('sparse') files, internal fragmentation, indirect blocks, and the like -B, --block-size=SIZE scale sizes by SIZE before printing them; e.g., '-BM' prints sizes in units of 1,048,576 bytes; see SIZE format below -b, --bytes equivalent to '--apparent-size --block-size=1' -c, --total produce a grand total -D, --dereference-args dereference only symlinks that are listed on the command line -d, --max-depth=N print the total for a directory (or file, with --all) only if it is N or fewer levels below the command line argument; --max-depth=0 is the same as --summarize --files0-from=F summarize disk usage of the --More--
Use with certain commands, the –help option is not valid:
root@debian8:~# type --help -su: type: --: invalid option type: usage: type [-afptP] name [name ...]
root@ubuntu1604:~# type --help -su: type: --: invalid option type: usage: type [-afptP] name [name ...]
[root@centos7 ~]# type --help -bash: type: --: invalid option type: usage: type [-afptP] name [name ...]
SLES12SP1:~ # type --help -bash: type: --: invalid option type: usage: type [-afptP] name [name ...]
Help on built-in commands
Commands such as type, cd or umask are internal to the shell:
root@debian8:~# type type type is a shell builtin
root@ubuntu1604:~# type type type is a shell builtin
[root@centos7 ~]# type type type is a shell builtin
SLES12SP1:~ # type type type is a shell builtin
One of the internal Bash commands is help. Used with no argument, this command shows a list of all the internal commands:
root@debian8:~# help | more GNU bash, version 4.3.30(1)-release (x86_64-pc-linux-gnu) These shell commands are defined internally. Type `help' to see this list. Type `help name' to find out more about the function `name'. Use `info bash' to find out more about the shell in general. Use `man -k' or `info' to find out more about commands not in this list. A star (*) next to a name means that the command is disabled. job_spec [&] history [-c] [-d offset] [n] or history -a> (( expression )) if COMMANDS; then COMMANDS; [ elif COMMAND> . filename [arguments] jobs [-lnprs] [jobspec ...] or jobs -x com> : kill [-s sigspec | -n signum | -sigspec] p> [ arg... ] let arg [arg ...] [[ expression ]] local [option] name[=value] ... alias [-p] [name[=value] ... ] logout [n] bg [job_spec ...] mapfile [-n count] [-O origin] [-s count] > bind [-lpsvPSVX] [-m keymap] [-f filename] > popd [-n] [+N | -N] break [n] printf [-v var] format [arguments] builtin [shell-builtin [arg ...]] pushd [-n] [+N | -N | dir] caller [expr] pwd [-LP] case WORD in [PATTERN [| PATTERN]...) COMMA> read [-ers] [-a array] [-d delim] [-i text> cd [-L|[-P [-e]] [-@]] [dir] readarray [-n count] [-O origin] [-s count> command [-pVv] command [arg ...] readonly [-aAf] [name[=value] ...] or read> --More--
root@ubuntu1604:~# help | more GNU bash, version 4.3.42(1)-release (x86_64-pc-linux-gnu) These shell commands are defined internally. Type `help' to see this list. Type `help name' to find out more about the function `name'. Use `info bash' to find out more about the shell in general. Use `man -k' or `info' to find out more about commands not in this list. A star (*) next to a name means that the command is disabled. job_spec [&] history [-c] [-d offset] [n] or history -> (( expression )) if COMMANDS; then COMMANDS; [ elif COMMAN> . filename [arguments] jobs [-lnprs] [jobspec ...] or jobs -x co> : kill [-s sigspec | -n signum | -sigspec] > [ arg... ] let arg [arg ...] [[ expression ]] local [option] name[=value] ... alias [-p] [name[=value] ... ] logout [n] bg [job_spec ...] mapfile [-n count] [-O origin] [-s count]> bind [-lpsvPSVX] [-m keymap] [-f filename]> popd [-n] [+N | -N] break [n] printf [-v var] format [arguments] builtin [shell-builtin [arg ...]] pushd [-n] [+N | -N | dir] caller [expr] pwd [-LP] case WORD in [PATTERN [| PATTERN]...) COMM> read [-ers] [-a array] [-d delim] [-i tex> cd [-L|[-P [-e]] [-@]] [dir] readarray [-n count] [-O origin] [-s coun> command [-pVv] command [arg ...] readonly [-aAf] [name[=value] ...] or rea> --More--
[root@centos7 ~]# help | more GNU bash, version 4.2.46(1)-release (x86_64-redhat-linux-gnu) These shell commands are defined internally. Type `help' to see this list. Type `help name' to find out more about the function `name'. Use `info bash' to find out more about the shell in general. Use `man -k' or `info' to find out more about commands not in this list. A star (*) next to a name means that the command is disabled. job_spec [&] history [-c] [-d offset] [n] or history -anr> (( expression )) if COMMANDS; then COMMANDS; [ elif COMMANDS;> . filename [arguments] jobs [-lnprs] [jobspec ...] or jobs -x comma> : kill [-s sigspec | -n signum | -sigspec] pid> [ arg... ] let arg [arg ...] [[ expression ]] local [option] name[=value] ... alias [-p] [name[=value] ... ] logout [n] bg [job_spec ...] mapfile [-n count] [-O origin] [-s count] [-> bind [-lpvsPVS] [-m keymap] [-f filename] [-q> popd [-n] [+N | -N] break [n] printf [-v var] format [arguments] builtin [shell-builtin [arg ...]] pushd [-n] [+N | -N | dir] caller [expr] pwd [-LP] case WORD in [PATTERN [| PATTERN]...) COMMAND> read [-ers] [-a array] [-d delim] [-i text] > cd [-L|[-P [-e]]] [dir] readarray [-n count] [-O origin] [-s count] > command [-pVv] command [arg ...] readonly [-aAf] [name[=value] ...] or readon> --More--
SLES12SP1:~ # help | more GNU bash, version 4.2.47(1)-release (x86_64-suse-linux-gnu) These shell commands are defined internally. Type `help' to see this list. Type `help name' to find out more about the function `name'. Use `info bash' to find out more about the shell in general. Use `man -k' or `info' to find out more about commands not in this list. A star (*) next to a name means that the command is disabled. job_spec [&] history [-c] [-d offset] [n] or history -anrw> (( expression )) if COMMANDS; then COMMANDS; [ elif COMMANDS; > . filename [arguments] jobs [-lnprs] [jobspec ...] or jobs -x comman> : kill [-s sigspec | -n signum | -sigspec] pid > [ arg... ] let arg [arg ...] [[ expression ]] local [option] name[=value] ... alias [-p] [name[=value] ... ] logout [n] bg [job_spec ...] mapfile [-n count] [-O origin] [-s count] [-t> bind [-lpvsPVS] [-m keymap] [-f filename] [-q > popd [-n] [+N | -N] break [n] printf [-v var] format [arguments] builtin [shell-builtin [arg ...]] pushd [-n] [+N | -N | dir] caller [expr] pwd [-LP] case WORD in [PATTERN [| PATTERN]...) COMMANDS> read [-ers] [-a array] [-d delim] [-i text] [> cd [-L|[-P [-e]]] [dir] readarray [-n count] [-O origin] [-s count] [> command [-pVv] command [arg ...] readonly [-aAf] [name[=value] ...] or readonl> --More--
To get help concerning a given internal command, help is invoked with the given command as an argument:
root@debian8:~# help type type: type [-afptP] name [name ...] Display information about command type. For each NAME, indicate how it would be interpreted if used as a command name. Options: -a display all locations containing an executable named NAME; includes aliases, builtins, and functions, if and only if the `-p' option is not also used -f suppress shell function lookup -P force a PATH search for each NAME, even if it is an alias, builtin, or function, and returns the name of the disk file that would be executed -p returns either the name of the disk file that would be executed, or nothing if `type -t NAME' would not return `file'. -t output a single word which is one of `alias', `keyword', `function', `builtin', `file' or `', if NAME is an alias, shell reserved word, shell function, shell builtin, disk file, or not found, respectively Arguments: NAME Command name to be interpreted. Exit Status: Returns success if all of the NAMEs are found; fails if any are not found.
root@ubuntu1604:~# help type type: type [-afptP] name [name ...] Display information about command type. For each NAME, indicate how it would be interpreted if used as a command name. Options: -a display all locations containing an executable named NAME; includes aliases, builtins, and functions, if and only if the `-p' option is not also used -f suppress shell function lookup -P force a PATH search for each NAME, even if it is an alias, builtin, or function, and returns the name of the disk file that would be executed -p returns either the name of the disk file that would be executed, or nothing if `type -t NAME' would not return `file'. -t output a single word which is one of `alias', `keyword', `function', `builtin', `file' or `', if NAME is an alias, shell reserved word, shell function, shell builtin, disk file, or not found, respectively Arguments: NAME Command name to be interpreted. Exit Status: Returns success if all of the NAMEs are found; fails if any are not found.
[root@centos7 ~]# help type type: type [-afptP] name [name ...] Display information about command type. For each NAME, indicate how it would be interpreted if used as a command name. Options: -a display all locations containing an executable named NAME; includes aliases, builtins, and functions, if and only if the `-p' option is not also used -f suppress shell function lookup -P force a PATH search for each NAME, even if it is an alias, builtin, or function, and returns the name of the disk file that would be executed -p returns either the name of the disk file that would be executed, or nothing if `type -t NAME' would not return `file'. -t output a single word which is one of `alias', `keyword', `function', `builtin', `file' or `', if NAME is an alias, shell reserved word, shell function, shell builtin, disk file, or not found, respectively Arguments: NAME Command name to be interpreted. Exit Status: Returns success if all of the NAMEs are found; fails if any are not found. typeset: typeset [-aAfFgilrtux] [-p] name[=value] ... Set variable values and attributes. Obsolete. See `help declare'.
SLES12SP1:~ # help type type: type [-afptP] name [name ...] Display information about command type. For each NAME, indicate how it would be interpreted if used as a command name. Options: -a display all locations containing an executable named NAME; includes aliases, builtins, and functions, if and only if the `-p' option is not also used -f suppress shell function lookup -P force a PATH search for each NAME, even if it is an alias, builtin, or function, and returns the name of the disk file that would be executed -p returns either the name of the disk file that would be executed, or nothing if `type -t NAME' would not return `file'. -t output a single word which is one of `alias', `keyword', `function', `builtin', `file' or `', if NAME is an alias, shell reserved word, shell function, shell builtin, disk file, or not found, respectively Arguments: NAME Command name to be interpreted. Exit Status: Returns success if all of the NAMEs are found; fails if any are not found. typeset: typeset [-aAfFgilrtux] [-p] name[=value] ... Set variable values and attributes. Obsolete. See `help declare'.
The man command
The man command is used to consult the manual of the command passed as an argument. For example man help under RHEL/CentOS 7 and SLES 12 produces the following output:
BASH_BUILTINS(1) General Commands Manual BASH_BUILTINS(1) NAME bash, :, ., [, alias, bg, bind, break, builtin, caller, cd, command, compgen, com‐ plete, compopt, continue, declare, dirs, disown, echo, enable, eval, exec, exit, export, false, fc, fg, getopts, hash, help, history, jobs, kill, let, local, logout, mapfile, popd, printf, pushd, pwd, read, readonly, return, set, shift, shopt, source, suspend, test, times, trap, true, type, typeset, ulimit, umask, unalias, unset, wait - bash built-in commands, see bash(1) BASH BUILTIN COMMANDS Unless otherwise noted, each builtin command documented in this section as accepting options preceded by - accepts -- to signify the end of the options. The :, true, false, and test builtins do not accept options and do not treat -- specially. The exit, logout, break, continue, let, and shift builtins accept and process arguments beginning with - without requiring --. Other builtins that accept arguments but are not specified as accepting options interpret arguments beginning with - as invalid options and require -- to prevent this interpretation. : [arguments] No effect; the command does nothing beyond expanding arguments and performing any specified redirections. A zero exit code is returned. . filename [arguments] Manual page help(1) line 1 (press h for help or q to quit)
In certain cases, such as with Debian 8 and Ubuntu 16.04 LTS for the help command, the manual is not available:
root@debian8:~# man help No manual entry for help
root@ubuntu1604:~# man help No manual entry for help
Each manual page can contain several sections:
Section | Contents |
---|---|
NAME | This section is required and has a standardized format consisting of a comma-separated list of program or function names, followed by a dash, followed by a short description of the functionality the program (or function, or file) is supposed to provide. By using the makewhatis command, the name sections are inputted into the whatis database files. |
SYNOPSIS | This section gives a short overview on available program options. For functions this section lists corresponding include files and the prototype so the programmer knows the type and number of arguments as well as the return type. |
DESCRIPTION | This section describes how to use the command or function and what each argument does. |
OPTIONS | This section gives a description of how each option affects program behaviour. |
FILES | This section lists files the program or function uses. |
EXAMPLE | This section gives examples of how to use the command or function. |
ENVIRONMENT | This section lists all environment variables that affect the program or function and explains how they do so. |
CONFORMING TO | This section lists the eventual standards that the command or function conforms to. |
BUGS / TO DO | This section describes the limitations and known inconveniences of the command or function. |
EXIT STATUS / RETURN VALUE | This section lists the exit status codes and their meaning. |
SEE ALSO | This section provides a list of related man pages in alphabetical order. |
Navigation within a manual is accomplished using the following keys:
Key | Function |
---|---|
Space Bar | Move forward one screen |
↵ Enter | Move down one line |
↑ | Move up one line |
↓ | Move down one line |
Page↑ | Move up (backwards) one half screen |
Page↓ | Move down (forward) one half screen |
Home | Move to the beginning of the manual |
End | Move to the end of the manual |
/ | Search for the string that follows the / key. The n key then searches for the next occurrence whilst the N searches for the previous occurrence |
Q | Quit the manual |
A complete Linux manual is comprised of up to 9 sections:
Section | Contents |
---|---|
1 | Executable programs or shell commands |
2 | System calls (functions provided by the kernel) |
3 | Library calls (functions within program libraries) |
4 | Special files (usually found in /dev) |
5 | File formats and conventions eg /etc/passwd |
6 | Games |
7 | Miscellaneous (including macro packages and conventions), e.g. man(7), groff(7) |
8 | System administration commands (usually only for root) |
9 | Kernel routines [Non standard] |
The available section for a specific command are given by the output of the whereis command:
root@debian8:~# whereis passwd passwd: /usr/bin/passwd /etc/passwd /usr/share/man/man1/passwd.1ssl.gz /usr/share/man/man1/passwd.1.gz /usr/share/man/man5/passwd.5.gz
root@ubuntu1604:~# whereis passwd passwd: /usr/bin/passwd /etc/passwd /usr/share/man/man5/passwd.5.gz /usr/share/man/man1/passwd.1.gz /usr/share/man/man1/passwd.1ssl.gz
[root@centos7 ~]# whereis passwd passwd: /usr/bin/passwd /etc/passwd /usr/share/man/man1/passwd.1.gz /usr/share/man/man5/passwd.5.gz
SLES12SP1:~ # whereis passwd passwd: /usr/bin/passwd /etc/passwd /etc/passwd.YaST2save /usr/share/man/man1/passwd.1ssl.gz /usr/share/man/man1/passwd.1.gz /usr/share/man/man5/passwd.5.gz
To consult a specific section of a manual, the section number must be supplied as an argument to the man command:
$ man 5 passwd [Enter]
The -k option of the man command searches for the string supplied as an argument within the list of available manuals:
root@debian8:~# man -k passwd chgpasswd (8) - update group passwords in batch mode chpasswd (8) - update passwords in batch mode exim4_passwd (5) - Files in use by the Debian exim4 packages exim4_passwd_client (5) - Files in use by the Debian exim4 packages gpasswd (1) - administer /etc/group and /etc/gshadow grub-mkpasswd-pbkdf2 (1) - generate hashed password for GRUB lppasswd (1) - add, change, or delete digest passwords. mkpasswd (1) - Overfeatured front end to crypt(3) pam_localuser (8) - require users to be listed in /etc/passwd passwd (1) - change user password passwd (1ssl) - compute password hashes passwd (5) - the password file update-passwd (8) - safely update /etc/passwd, /etc/shadow and /etc/groupword
root@ubuntu1604:~# man -k passwd chgpasswd (8) - update group passwords in batch mode chpasswd (8) - update passwords in batch mode fgetpwent_r (3) - get passwd file entry reentrantly getpwent_r (3) - get passwd file entry reentrantly gpasswd (1) - administer /etc/group and /etc/gshadow grub-mkpasswd-pbkdf2 (1) - generate hashed password for GRUB pam_localuser (8) - require users to be listed in /etc/passwd passwd (1) - change user password passwd (1ssl) - compute password hashes passwd (5) - the password file passwd2des (3) - RFS password encryption update-passwd (8) - safely update /etc/passwd, /etc/shadow and /etc/group
[root@centos7 ~]# man -k passwd chpasswd (8) - update passwords in batch mode fgetpwent_r (3) - get passwd file entry reentrantly getpwent_r (3) - get passwd file entry reentrantly gpasswd (1) - administer /etc/group and /etc/gshadow grub2-mkpasswd-pbkdf2 (1) - Generate a PBKDF2 password hash. kpasswd (1) - change a user's Kerberos password lpasswd (1) - Change group or user password lppasswd (1) - add, change, or delete digest passwords. pam_localuser (8) - require users to be listed in /etc/passwd passwd (1) - update user's authentication tokens sslpasswd (1ssl) - compute password hashes passwd (5) - password file passwd2des (3) - RFS password encryption pwhistory_helper (8) - Helper binary that transfers password hashes from passwd or shadow to ... smbpasswd (5) - The Samba encrypted password file smbpasswd (8) - change a user's SMB password userpasswd (1) - A graphical tool to allow users to change their passwords. vncpasswd (1) - change the VNC password
SLES12SP1:~ # man -k passwd chpasswd (8) - update passwords in batch mode Crypt::SmbHash (3pm) - Perl-only implementation of lanman and nt md4 hash functions, for use in... fgetpwent_r (3) - get passwd file entry reentrantly getpwent_r (3) - get passwd file entry reentrantly gpasswd (1) - administer /etc/group grub2-mkpasswd-pbkdf2 (1) - generate hashed password for GRUB ldappasswd (1) - change the password of an LDAP entry lppasswd (1) - add, change, or delete digest passwords. opiepasswd (1) - Change or set a user's password for the OPIE authentication system. pam_localuser (8) - require users to be listed in /etc/passwd passwd (1) - change user password passwd (1ssl) - compute password hashes passwd (5) - password file passwd2des (3) - RFS password encryption saslpasswd2 (8) - set a user's sasl password smbpasswd (5) - The Samba encrypted password file smbpasswd (8) - change a user's SMB password vncpasswd (1) - change the VNC password yppasswd (1) - change your password in the NIS database
The output is a list of the available manuals complete with their description. The number between parentheses indicates the manual section number.
Command Line Switches
The switches associated with the man command are:
root@debian8:~# man --help Usage: man [OPTION...] [SECTION] PAGE... -C, --config-file=FILE use this user configuration file -d, --debug emit debugging messages -D, --default reset all options to their default values --warnings[=WARNINGS] enable warnings from groff Main modes of operation: -f, --whatis equivalent to whatis -k, --apropos equivalent to apropos -K, --global-apropos search for text in all pages -l, --local-file interpret PAGE argument(s) as local filename(s) -w, --where, --path, --location print physical location of man page(s) -W, --where-cat, --location-cat print physical location of cat file(s) -c, --catman used by catman to reformat out of date cat pages -R, --recode=ENCODING output source page encoded in ENCODING Finding manual pages: -L, --locale=LOCALE define the locale for this particular man search -m, --systems=SYSTEM use manual pages from other systems -M, --manpath=PATH set search path for manual pages to PATH -S, -s, --sections=LIST use colon separated section list -e, --extension=EXTENSION limit search to extension type EXTENSION -i, --ignore-case look for pages case-insensitively (default) -I, --match-case look for pages case-sensitively --regex show all pages matching regex --wildcard show all pages matching wildcard --names-only make --regex and --wildcard match page names only, not descriptions -a, --all find all matching manual pages -u, --update force a cache consistency check --no-subpages don't try subpages, e.g. 'man foo bar' => 'man foo-bar' Controlling formatted output: -P, --pager=PAGER use program PAGER to display output -r, --prompt=STRING provide the `less' pager with a prompt -7, --ascii display ASCII translation of certain latin1 chars -E, --encoding=ENCODING use selected output encoding --no-hyphenation, --nh turn off hyphenation --no-justification, --nj turn off justification -p, --preprocessor=STRING STRING indicates which preprocessors to run: e - [n]eqn, p - pic, t - tbl, g - grap, r - refer, v - vgrind -t, --troff use groff to format pages -T, --troff-device[=DEVICE] use groff with selected device -H, --html[=BROWSER] use www-browser or BROWSER to display HTML output -X, --gxditview[=RESOLUTION] use groff and display through gxditview (X11): -X = -TX75, -X100 = -TX100, -X100-12 = -TX100-12 -Z, --ditroff use groff and force it to produce ditroff -?, --help give this help list --usage give a short usage message -V, --version print program version Mandatory or optional arguments to long options are also mandatory or optional for any corresponding short options. Report bugs to cjwatson@debian.org.
The apropos command
apropos searches the whatis database for instances of a keyword passed to the command as an argument. With no further options, the output is identical to man -k:
root@debian8:~# apropos passwd chgpasswd (8) - update group passwords in batch mode chpasswd (8) - update passwords in batch mode exim4_passwd (5) - Files in use by the Debian exim4 packages exim4_passwd_client (5) - Files in use by the Debian exim4 packages gpasswd (1) - administer /etc/group and /etc/gshadow grub-mkpasswd-pbkdf2 (1) - generate hashed password for GRUB lppasswd (1) - add, change, or delete digest passwords. mkpasswd (1) - Overfeatured front end to crypt(3) pam_localuser (8) - require users to be listed in /etc/passwd passwd (1) - change user password passwd (1ssl) - compute password hashes passwd (5) - the password file update-passwd (8) - safely update /etc/passwd, /etc/shadow and /etc/group
root@ubuntu1604:~# apropos passwd chgpasswd (8) - update group passwords in batch mode chpasswd (8) - update passwords in batch mode fgetpwent_r (3) - get passwd file entry reentrantly getpwent_r (3) - get passwd file entry reentrantly gpasswd (1) - administer /etc/group and /etc/gshadow grub-mkpasswd-pbkdf2 (1) - generate hashed password for GRUB pam_localuser (8) - require users to be listed in /etc/passwd passwd (1) - change user password passwd (1ssl) - compute password hashes passwd (5) - the password file passwd2des (3) - RFS password encryption update-passwd (8) - safely update /etc/passwd, /etc/shadow and /etc/group
[root@centos7 ~]# apropos passwd chpasswd (8) - update passwords in batch mode fgetpwent_r (3) - get passwd file entry reentrantly getpwent_r (3) - get passwd file entry reentrantly gpasswd (1) - administer /etc/group and /etc/gshadow grub2-mkpasswd-pbkdf2 (1) - Generate a PBKDF2 password hash. kpasswd (1) - change a user's Kerberos password lpasswd (1) - Change group or user password lppasswd (1) - add, change, or delete digest passwords. pam_localuser (8) - require users to be listed in /etc/passwd passwd (1) - update user's authentication tokens sslpasswd (1ssl) - compute password hashes passwd (5) - password file passwd2des (3) - RFS password encryption pwhistory_helper (8) - Helper binary that transfers password hashes from passwd or shadow to ... smbpasswd (5) - The Samba encrypted password file smbpasswd (8) - change a user's SMB password userpasswd (1) - A graphical tool to allow users to change their passwords. vncpasswd (1) - change the VNC password
SLES12SP1:~ # apropos passwd chpasswd (8) - update passwords in batch mode Crypt::SmbHash (3pm) - Perl-only implementation of lanman and nt md4 hash functions, for use in... fgetpwent_r (3) - get passwd file entry reentrantly getpwent_r (3) - get passwd file entry reentrantly gpasswd (1) - administer /etc/group grub2-mkpasswd-pbkdf2 (1) - generate hashed password for GRUB ldappasswd (1) - change the password of an LDAP entry lppasswd (1) - add, change, or delete digest passwords. opiepasswd (1) - Change or set a user's password for the OPIE authentication system. pam_localuser (8) - require users to be listed in /etc/passwd passwd (1) - change user password passwd (1ssl) - compute password hashes passwd (5) - password file passwd2des (3) - RFS password encryption saslpasswd2 (8) - set a user's sasl password smbpasswd (5) - The Samba encrypted password file smbpasswd (8) - change a user's SMB password vncpasswd (1) - change the VNC password yppasswd (1) - change your password in the NIS database
Command Line Switches
The switches associated with the apropos command are:
root@debian8:~# apropos --help Usage: apropos [OPTION...] KEYWORD... -d, --debug emit debugging messages -v, --verbose print verbose warning messages -e, --exact search each keyword for exact match -r, --regex interpret each keyword as a regex -w, --wildcard the keyword(s) contain wildcards -a, --and require all keywords to match -l, --long do not trim output to terminal width -C, --config-file=FILE use this user configuration file -L, --locale=LOCALE define the locale for this search -m, --systems=SYSTEM use manual pages from other systems -M, --manpath=PATH set search path for manual pages to PATH -s, --sections=LIST, --section=LIST search only these sections (colon-separated) -?, --help give this help list --usage give a short usage message -V, --version print program version Mandatory or optional arguments to long options are also mandatory or optional for any corresponding short options. The --regex option is enabled by default. Report bugs to cjwatson@debian.org.
The makewhatis and whatis Commands under RHEL/CentOS 6
Each manual page has a short description available within it. These descriptions as well as the name of the manual are stored in the whatis database. The whatis database is created by /usr/sbin/makewhatis.
The use of makewhatis is extremely simple:
[root@centos6 ~]# makewhatis
The whatis command can now be used to identify the man sections available for the passwd command:
[root@centos6 ~]# whatis passwd passwd (1) - update user's authentication tokens passwd (5) - password file passwd [sslpasswd] (1ssl) - compute password hashes
Command Line Switches
The switches associated with the makewhatis command are:
[root@centos6 ~]# makewhatis --help Usage: makewhatis [-s sections] [-u] [-v] [-w] [manpath] [-c [catpath]] [-o whatisdb] This will build the whatis database for the man pages found in manpath and the cat pages found in catpath. -s: sections (default: 1 1p 8 2 3 3p 4 5 6 7 9 0p n l p o 1x 2x 3x 4x 5x 6x 7x 8x) -u: update database with pages added today -U: update database with pages added since last makewhatis run -v: verbose -o: location of whatis database (default: /var/cache/man/whatis) -w: use manpath obtained from `man --path` [manpath]: man directories (default: /usr/share/man) [catpath]: cat directories (default: the first existing directory in /usr/share/man)
The switches associated with the whatis command are:
Usage: whatis [OPTION...] KEYWORD... -d, --debug emit debugging messages -v, --verbose print verbose warning messages -r, --regex interpret each keyword as a regex -w, --wildcard the keyword(s) contain wildcards -l, --long do not trim output to terminal width -C, --config-file=FILE use this user configuration file -L, --locale=LOCALE define the locale for this search -m, --systems=SYSTEM use manual pages from other systems -M, --manpath=PATH set search path for manual pages to PATH -s, --section=SECTION search only this section -?, --help give this help list --usage give a short usage message -V, --version print program version Mandatory or optional arguments to long options are also mandatory or optional for any corresponding short options. Report bugs to cjwatson@debian.org.
The mandb and whatis commands under RHEL/CentOS 7, Debian 6, 7 and 8, SLES 11 and 12, Ubuntu 14.04 and 16.04
Under RHEL/CentOS 7, Debian 6, 7 and 8, SLES 11 and 12, Ubuntu 14.04 and 16.04 the database is maintained by root by using the /bin/mandb or /usr/bin/mandb command.
Once again, the use of mandb is very simple:
root@debian8:~# mandb Purging old database entries in /usr/share/man... Processing manual pages under /usr/share/man... Purging old database entries in /usr/share/man/ug... Processing manual pages under /usr/share/man/ug... Purging old database entries in /usr/share/man/tr... Processing manual pages under /usr/share/man/tr... Purging old database entries in /usr/share/man/el... Processing manual pages under /usr/share/man/el... Purging old database entries in /usr/share/man/ja... Processing manual pages under /usr/share/man/ja... ... 0 man subdirectories contained newer manual pages. 0 manual pages were added. 0 stray cats were added. 0 old database entries were purged.
root@ubuntu1604:~# mandb Purging old database entries in /usr/share/man... Processing manual pages under /usr/share/man... Purging old database entries in /usr/share/man/lv... Processing manual pages under /usr/share/man/lv... Purging old database entries in /usr/share/man/pt_BR... Processing manual pages under /usr/share/man/pt_BR... Purging old database entries in /usr/share/man/tr... Processing manual pages under /usr/share/man/tr... Purging old database entries in /usr/share/man/ca... Processing manual pages under /usr/share/man/ca... ... 0 man subdirectories contained newer manual pages. 0 manual pages were added. 0 stray cats were added. 0 old database entries were purged.
[root@centos7 ~]# mandb Purging old database entries in /usr/share/man... mandb: warning: /usr/share/man/man8/fsck.fat.8.manpage-fix.gz: ignoring bogus filename Processing manual pages under /usr/share/man... Purging old database entries in /usr/share/man/ca... Processing manual pages under /usr/share/man/ca... Purging old database entries in /usr/share/man/cs... Processing manual pages under /usr/share/man/cs... Purging old database entries in /usr/share/man/da... Processing manual pages under /usr/share/man/da... Purging old database entries in /usr/share/man/de... Processing manual pages under /usr/share/man/de... Purging old database entries in /usr/share/man/en... ... 0 man subdirectories contained newer manual pages. 0 manual pages were added. 0 stray cats were added. 0 old database entries were purged.
SLES12SP1:~ # mandb mandb: warning: $MANPATH set, ignoring /etc/manpath.config Purging old database entries in /usr/share/man/ca... Processing manual pages under /usr/share/man/ca... Purging old database entries in /usr/share/man/cs... Processing manual pages under /usr/share/man/cs... Purging old database entries in /usr/share/man/da... Processing manual pages under /usr/share/man/da... Purging old database entries in /usr/share/man/de... Processing manual pages under /usr/share/man/de... Purging old database entries in /usr/share/man/es... Processing manual pages under /usr/share/man/es... ... 10 man subdirectories contained newer manual pages. 0 manual pages were added. 0 stray cats were added. 0 old database entries were purged.
Now the whatis command can be used to check which manual sections are available for a specific command:
root@debian8:~# whatis passwd passwd (1) - change user password passwd (5) - the password file passwd (1ssl) - compute password hashes
root@ubuntu1604:~# whatis passwd passwd (1) - change user password passwd (1ssl) - compute password hashes passwd (5) - the password file
[root@centos7 ~]# whatis passwd sslpasswd (1ssl) - compute password hashes passwd (1) - update user's authentication tokens passwd (5) - password file
SLES12SP1:~ # whatis passwd passwd (1ssl) - compute password hashes passwd (1) - change user password passwd (5) - password file
Command Line Switches
The switches associated with the mandb command are:
root@debian8:~# mandb --help Usage: mandb [OPTION...] [MANPATH] -c, --create create dbs from scratch, rather than updating -C, --config-file=FILE use this user configuration file -d, --debug emit debugging messages -f, --filename=FILENAME update just the entry for this filename -p, --no-purge don't purge obsolete entries from the dbs -q, --quiet work quietly, except for 'bogus' warning -s, --no-straycats don't look for or add stray cats to the dbs -t, --test check manual pages for correctness -u, --user-db produce user databases only -?, --help give this help list --usage give a short usage message -V, --version print program version Mandatory or optional arguments to long options are also mandatory or optional for any corresponding short options. Report bugs to cjwatson@debian.org.
The switches associated with the whatis command are:
root@debian8:~# whatis --help Usage: whatis [OPTION...] KEYWORD... -d, --debug emit debugging messages -v, --verbose print verbose warning messages -r, --regex interpret each keyword as a regex -w, --wildcard the keyword(s) contain wildcards -l, --long do not trim output to terminal width -C, --config-file=FILE use this user configuration file -L, --locale=LOCALE define the locale for this search -m, --systems=SYSTEM use manual pages from other systems -M, --manpath=PATH set search path for manual pages to PATH -s, --sections=LIST, --section=LIST search only these sections (colon-separated) -?, --help give this help list --usage give a short usage message -V, --version print program version Mandatory or optional arguments to long options are also mandatory or optional for any corresponding short options. Report bugs to cjwatson@debian.org.
The info command
In addition to the man system, information regarding programs and commands can also be found using the info system. Background information, tutorials, and detailed information on using the program in question are sometimes lacking in man pages and as a result the info system was created to resolve that issue.
Within the info system, multiple individual pages of information make up the entire set of info pages for each specific application. These pages of information are referred to as nodes. You can page through nodes one at a time, or you can jump to specific pages through the use of hypertext links.
To help node navigation, info pages all display a header across the top of the page. This header includes information such as the current node, next and previous nodes, and information regarding the parent node. Navigation is accomplished using the following keys :
Key | Function |
---|---|
n | Next node. |
p | Previous node. |
u | Parent node. |
Space | Scroll down one page at a time. |
Del | Scroll up one page at a time. |
b | Return to the beginning of the current node. |
Tab ⇆ | Select next hypertext link. |
m <link text> | Performs a direct jump to the specified subnode. Pressing Tab displays all available subnodes. |
↵ Enter | Follow current hypertext link. Hypertext links are designated by an asterisk * at the beginning of the link, and a colon : at the end of the link. |
q | Quit the info system. |
To access the top node of the info system, use the following command :
root@debian8:~# info ... File: dir, Node: Top This is the top of the INFO tree This (the Directory node) gives a menu of major topics. Typing "q" exits, "?" lists all Info commands, "d" returns here, "h" gives a primer for first-timers, "mEmacs<Return>" visits the Emacs manual, etc. In Emacs, you can click mouse button 2 on a menu item or cross reference to select it. * Menu: Basics * Common options: (coreutils)Common options. * Coreutils: (coreutils). Core GNU (file, text, shell) utilities. * Date input formats: (coreutils)Date input formats. * File permissions: (coreutils)File permissions. Access modes. * Finding files: (find). Operating on files matching certain criteria. Compression * Gzip: (gzip). General (de)compression of files (lzw). -----Info: (dir)Top, 197 lines --Top-------------------------------------------------------- Welcome to Info version 5.2. Type h for help, m for menu item.
root@ubuntu1604:~# info ... File: dir, Node: Top, This is the top of the INFO tree. This is the Info main menu (aka directory node). A few useful Info commands: 'q' quits; '?' lists all Info commands; 'h' starts the Info tutorial; 'mTexinfo RET' visits the Texinfo manual, etc. * Menu: Basics * Common options: (coreutils)Common options. * Coreutils: (coreutils). Core GNU (file, text, shell) utilities. * Date input formats: (coreutils)Date input formats. * Ed: (ed). The GNU line editor * File permissions: (coreutils)File permissions. Access modes. * Finding files: (find). Operating on files matching certain criteria. C++ libraries -----Info: (dir)Top, 254 lines --Top------------------------------------------------------- Welcome to Info version 6.1. Type H for help, h for tutorial.
[root@centos7 ~]# info ... File: dir Node: Top This is the top of the INFO tree This (the Directory node) gives a menu of major topics. Typing "q" exits, "?" lists all Info commands, "d" returns here, "h" gives a primer for first-timers, "mEmacs<Return>" visits the Emacs topic, etc. In Emacs, you can click mouse button 2 on a menu item or cross reference to select it. * Menu: Archiving * Cpio: (cpio). Copy-in-copy-out archiver to tape or disk. * Tar: (tar). Making tape (or disk) archives. Basics * Common options: (coreutils)Common options. * Coreutils: (coreutils). Core GNU (file, text, shell) utilities. * Date input formats: (coreutils)Date input formats. * File permissions: (coreutils)File permissions. Access modes. -----Info: (dir)Top, 2027 lines --Top----------------------------------------------------------- Welcome to Info version 5.1. Type h for help, m for menu item.
SLES12SP1:~ # info ... File: dir, Node: Top This is the top of the INFO tree This (the Directory node) gives a menu of major topics. Typing "q" exits, "?" lists all Info commands, "d" returns here, "h" gives a primer for first-timers, "mEmacs<Return>" visits the Emacs manual, etc. In Emacs, you can click mouse button 2 on a menu item or cross reference to select it. * Menu: Archiving * Cpio: (cpio). Copy-in-copy-out archiver to tape or disk. * Shar utilities: (sharutils). Shell archiver, uuencode/uudecode. * Tar: (tar). Making tape (or disk) archives. Basics * Bash: (bash). The GNU Bourne-Again SHell. * Common options: (coreutils)Common options. * Coreutils: (coreutils). Core GNU (file, text, shell) utilities. * Date input formats: (coreutils)Date input formats. -----Info: (dir)Top, 321 lines --Top-------------------------------------------------------------- Welcome to Info version 4.13. Type h for help, m for menu item.
Note that the version of the info command differs from one distribution to another:
root@debian8:~# info -O --version info (GNU texinfo) 5.2 Copyright (C) 2013 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.
root@ubuntu1604:~# info -O --version info (GNU texinfo) 6.1 Copyright (C) 2016 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.
[root@centos7 ~]# info -O --version info (GNU texinfo) 5.1 Copyright (C) 2013 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.
SLES12SP1:~ # info -O --version info (GNU texinfo) 4.13 Copyright (C) 2008 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.
Command Line Switches
The switches associated with the info command are:
root@debian8:~# info --help Usage: info [OPTION]... [MENU-ITEM...] Read documentation in Info format. Options: -a, --all use all matching manuals. -k, --apropos=STRING look up STRING in all indices of all manuals. -d, --directory=DIR add DIR to INFOPATH. --dribble=FILE remember user keystrokes in FILENAME. -f, --file=MANUAL specify Info manual to visit. -h, --help display this help and exit. --index-search=STRING go to node pointed by index entry STRING. -n, --node=NODENAME specify nodes in first visited Info file. -o, --output=FILE output selected nodes to FILE. -R, --raw-escapes output "raw" ANSI escapes (default). --no-raw-escapes output escapes as literal text. --restore=FILE read initial keystrokes from FILE. -O, --show-options, --usage go to command-line options node. --strict-node-location (for debugging) use Info file pointers as-is. --subnodes recursively output menu items. -v, --variable VAR=VALUE assign VALUE to Info variable VAR. --vi-keys use vi-like and less-like key bindings. --version display version information and exit. -w, --where, --location print physical location of Info file. -x, --debug=NUMBER set debugging level (-1 for all). The first non-option argument, if present, is the menu entry to start from; it is searched for in all `dir' files along INFOPATH. If it is not present, info merges all `dir' files and shows the result. Any remaining arguments are treated as the names of menu items relative to the initial node visited. For a summary of key bindings, type h within Info. Examples: info show top-level dir menu info info show the general manual for Info readers info info-stnd show the manual specific to this Info program info emacs start at emacs node from top-level dir info emacs buffers start at buffers node within emacs manual info --show-options emacs start at node with emacs' command line options info --subnodes -o out.txt emacs dump entire manual to out.txt info -f ./foo.info show file ./foo.info, not searching dir Email bug reports to bug-texinfo@gnu.org, general questions and discussion to help-texinfo@gnu.org. Texinfo home page: http://www.gnu.org/software/texinfo/
root@ubuntu1604:~# info --help Usage: info [OPTION]... [MENU-ITEM...] Read documentation in Info format. Options: -a, --all use all matching manuals. -k, --apropos=STRING look up STRING in all indices of all manuals. -d, --directory=DIR add DIR to INFOPATH. --dribble=FILE remember user keystrokes in FILENAME. -f, --file=MANUAL specify Info manual to visit. -h, --help display this help and exit. --index-search=STRING go to node pointed by index entry STRING. -n, --node=NODENAME specify nodes in first visited Info file. -o, --output=FILE output selected nodes to FILE. -R, --raw-escapes output "raw" ANSI escapes (default). --no-raw-escapes output escapes as literal text. --restore=FILE read initial keystrokes from FILE. -O, --show-options, --usage go to command-line options node. --strict-node-location (for debugging) use Info file pointers as-is. --subnodes recursively output menu items. -v, --variable VAR=VALUE assign VALUE to Info variable VAR. --vi-keys use vi-like and less-like key bindings. --version display version information and exit. -w, --where, --location print physical location of Info file. -x, --debug=NUMBER set debugging level (-1 for all). The first non-option argument, if present, is the menu entry to start from; it is searched for in all 'dir' files along INFOPATH. If it is not present, info merges all 'dir' files and shows the result. Any remaining arguments are treated as the names of menu items relative to the initial node visited. For a summary of key bindings, type H within Info. Examples: info show top-level dir menu info info show the general manual for Info readers info info-stnd show the manual specific to this Info program info emacs start at emacs node from top-level dir info emacs buffers select buffers menu entry in emacs manual info emacs -n Files start at Files node within emacs manual info '(emacs)Files' alternative way to start at Files node info --show-options emacs start at node with emacs' command line options info --subnodes -o out.txt emacs dump entire manual to out.txt info -f ./foo.info show file ./foo.info, not searching dir Email bug reports to bug-texinfo@gnu.org, general questions and discussion to help-texinfo@gnu.org. Texinfo home page: http://www.gnu.org/software/texinfo/
[root@centos7 ~]# info --help Usage: info [OPTION]... [MENU-ITEM...] Read documentation in Info format. Options: -k, --apropos=STRING look up STRING in all indices of all manuals. -d, --directory=DIR add DIR to INFOPATH. --dribble=FILENAME remember user keystrokes in FILENAME. -f, --file=FILENAME specify Info file to visit. -h, --help display this help and exit. --index-search=STRING go to node pointed by index entry STRING. -n, --node=NODENAME specify nodes in first visited Info file. -o, --output=FILENAME output selected nodes to FILENAME. -R, --raw-escapes output "raw" ANSI escapes (default). --no-raw-escapes output escapes as literal text. --restore=FILENAME read initial keystrokes from FILENAME. -O, --show-options, --usage go to command-line options node. --strict-node-location (for debugging) use Info file pointers as-is. --subnodes recursively output menu items. --vi-keys use vi-like and less-like key bindings. --version display version information and exit. -w, --where, --location print physical location of Info file. The first non-option argument, if present, is the menu entry to start from; it is searched for in all `dir' files along INFOPATH. If it is not present, info merges all `dir' files and shows the result. Any remaining arguments are treated as the names of menu items relative to the initial node visited. For a summary of key bindings, type h within Info. Examples: info show top-level dir menu info info show the general manual for Info readers info info-stnd show the manual specific to this Info program info emacs start at emacs node from top-level dir info emacs buffers start at buffers node within emacs manual info --show-options emacs start at node with emacs' command line options info --subnodes -o out.txt emacs dump entire manual to out.txt info -f ./foo.info show file ./foo.info, not searching dir Email bug reports to bug-texinfo@gnu.org, general questions and discussion to help-texinfo@gnu.org. Texinfo home page: http://www.gnu.org/software/texinfo/
SLES12SP1:~ # info --help Usage: info [OPTION]... [MENU-ITEM...] Read documentation in Info format. Options: -k, --apropos=STRING look up STRING in all indices of all manuals. -d, --directory=DIR add DIR to INFOPATH. --dribble=FILENAME remember user keystrokes in FILENAME. -f, --file=FILENAME specify Info file to visit. -h, --help display this help and exit. --index-search=STRING go to node pointed by index entry STRING. -n, --node=NODENAME specify nodes in first visited Info file. -o, --output=FILENAME output selected nodes to FILENAME. -R, --raw-escapes output "raw" ANSI escapes (default). --no-raw-escapes output escapes as literal text. --restore=FILENAME read initial keystrokes from FILENAME. -O, --show-options, --usage go to command-line options node. --subnodes recursively output menu items. --vi-keys use vi-like and less-like key bindings. --version display version information and exit. -w, --where, --location print physical location of Info file. The first non-option argument, if present, is the menu entry to start from; it is searched for in all `dir' files along INFOPATH. If it is not present, info merges all `dir' files and shows the result. Any remaining arguments are treated as the names of menu items relative to the initial node visited. For a summary of key bindings, type h within Info. Examples: info show top-level dir menu info info show the general manual for Info readers info info-stnd show the manual specific to this Info program info emacs start at emacs node from top-level dir info emacs buffers start at buffers node within emacs manual info --show-options emacs start at node with emacs' command line options info --subnodes -o out.txt emacs dump entire manual to out.txt info -f ./foo.info show file ./foo.info, not searching dir Email bug reports to bug-texinfo@gnu.org, general questions and discussion to help-texinfo@gnu.org. Texinfo home page: http://www.gnu.org/software/texinfo/
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Copyright © 2004-2017 Hugh Norris.<br><br> <a rel=“license” href=“http://creativecommons.org/licenses/by-nc-nd/3.0/”><img alt=“Creative Commons License” style=“border-width:0” src=“https://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png” /></a><br />This work is licensed under a <a rel=“license” href=“http://creativecommons.org/licenses/by-nc-nd/3.0/”>Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License</a>
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