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LDF103 - Aide et Documentation
L'Aide des Commandes Externes au Shell
Les commandes externes au shell sont des binaires exécutables ou des scripts, généralement situés dans /bin, /sbin, /usr/bin ou /usr/sbin :
root@debian9:~# type ifconfig ifconfig is /sbin/ifconfig
L'aide d'une commande externe au shell peut être visualisé dans la plupart des cas en passant le paramètre - -help en argument à la commande en question :
root@debian9:~# 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--
Cependant dans certains cas, cette option n'est pas admise :
root@debian9:~# type --help -su: type: --: invalid option type: usage: type [-afptP] name [name ...]
L'Aide des Commandes Internes du Shell
Les commandes internes au shell sont des commandes telles type, cd ou umask. Pour vérifier le type de commande, il faut utiliser la commande type :
root@debian9:~# type type type is a shell builtin
Le shell possède la commande help. Utilisée seule, cette commande fournit la liste des commandes internes :
root@debian9:~# 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--
L'aide concernant une commande spécifique peut être obtenu en passant la commande concernée en argument à la commande help :
root@debian9:~# 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.
La Commande man
La commande man donne accès au manuel de la commande passée en argument. Par exemple man passwd produit la sortie suivante :
PASSWD(1) User Commands PASSWD(1)
NAME
passwd - change user password
SYNOPSIS
passwd [options] [LOGIN]
DESCRIPTION
The passwd command changes passwords for user accounts. A normal user may only change the password for his/her own account, while the superuser may change
the password for any account. passwd also changes the account or associated password validity period.
Password Changes
The user is first prompted for his/her old password, if one is present. This password is then encrypted and compared against the stored password. The user
has only one chance to enter the correct password. The superuser is permitted to bypass this step so that forgotten passwords may be changed.
After the password has been entered, password aging information is checked to see if the user is permitted to change the password at this time. If not,
passwd refuses to change the password and exits.
The user is then prompted twice for a replacement password. The second entry is compared against the first and both are required to match in order for the
password to be changed.
Then, the password is tested for complexity. As a general guideline, passwords should consist of 6 to 8 characters including one or more characters from
each of the following sets:
· lower case alphabetics
· digits 0 thru 9
· punctuation marks
Care must be taken not to include the system default erase or kill characters. passwd will reject any password which is not suitably complex.
Hints for user passwords
The security of a password depends upon the strength of the encryption algorithm and the size of the key space. The legacy UNIX System encryption method is
based on the NBS DES algorithm. More recent methods are now recommended (see ENCRYPT_METHOD). The size of the key space depends upon the randomness of the
password which is selected.
Compromises in password security normally result from careless password selection or handling. For this reason, you should not select a password which
appears in a dictionary or which must be written down. The password should also not be a proper name, your license number, birth date, or street address.
Any of these may be used as guesses to violate system security.
You can find advices on how to choose a strong password on http://en.wikipedia.org/wiki/Password_strength
OPTIONS
Manual page passwd(1) line 1 (press h for help or q to quit)
Une page de manuel peut contenir plusieurs sections :
| Section | Contenu |
|---|---|
| NOM | Nom et rôle de la commande |
| SYNOPSIS | Syntaxe de la commande, paramètres et arguments |
| DESCRIPTION | Mode d'emploi et les arguments principaux |
| OPTIONS | Descriptions détaillées de chaque paramètre |
| EXEMPLES / EXAMPLES | Exemples d'utilisation de la commande |
| ENVIRONNEMENT / ENVIRONMENT VARIABLES | Fonctionnement selon l'environnement du shell |
| CONFORMITÉ / STANDARDS / CONFORMING TO | Éventuelles normes auxquelles la commande se conforme |
| BOGUES / BUGS/TO DO | Éventuelles bogues connues |
| DIAGNOSTICS/RETOUR / EXIT STATUS/RETURN VALUE | Codes d'erreur et leur signification |
| VOIR AUSSI / SEE ALSO | Commandes liées à celle du manuel actuel |
La navigation dans la page de manuel se fait grâce à l'utilisation de certaines touches :
| Touche | Fonction |
|---|---|
| Espace | Faire défiler une page complète |
| Entrée | Faire défiler la page ligne par ligne |
| ↑ | Faire défiler la page une ligne vers le haut |
| ↓ | Faire défiler la page une ligne vers le bas |
| PageHaut | Faire défiler une demi-page vers le haut |
| PageBas | Faire défiler une demi-page vers le bas |
| Début | Se positionner au début du manuel |
| Fin | Se positionner à la fin du manuel |
| / | Rechercher la chaîne qui suit la touche /. La touche n recherche l'occurrence suivante. La touche N recherche l'occurrence précédente |
| Q | Quitter le manuel |
Un manuel complet est fait de plusieurs sections :
| Section | Contenu |
|---|---|
| 1 | Instructions exécutables ou commandes shell |
| 2 | Appels système |
| 3 | Appels des bibliothèques |
| 4 | Fichiers spéciaux |
| 5 | Format des fichiers |
| 6 | Jeux, économiseurs d'écrans, gadgets |
| 7 | Divers et commandes non standard |
| 8 | Commandes d'administration du système Linux |
| 9 | Sous-programmes du noyau |
Les différentes sections disponibles sont visibles grâce à l'utilisation de la commande whereis :
root@debian9:~# 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
Pour visualiser une section spécifique, il convient de préciser son numéro :
$ man 5 passwd [Entrée]
L'option -k de la commande man permet de rechercher la chaîne passée en argument dans la liste des manuels disponibles :
root@debian9:~# 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
Le résultat est une liste de commandes suivies par une description brève de celles-ci.
Important - Notez que les numéros entre parenthèses indiquent les sections disponibles.
Options de la commande
Les options de cette commande sont :
root@debian9:~# 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.
La Commande apropos
La commande apropos cherche dans la base de données whatis la chaine de caractères passée en argument à la commande. Sans option, la sortie obtenue est identique à la commande man -k :
root@debian9:~# 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
Options de la commande
Les options de cette commande sont :
root@debian9:~# 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.
Les Commandes mandb et whatis
Sous Debian 6, 7, 8 et 9 la base de données peut être maintenue manuellement par root en invoquant l'exécutable /bin/mandb ou /usr/bin/mandb.
L'utilisation de mandb est très simple :
root@debian9:~# 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.
La commande whatis peut maintenant être utilisée pour identifier les sections des manuels disponibles pour une commande donnée :
root@debian9:~# whatis passwd passwd (1) - change user password passwd (5) - the password file passwd (1ssl) - compute password hashes
Options des commandes
Les options de la commande mandb sont :
root@debian9:~# 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.
Les options de la commande whatis sont :
root@debian9:~# 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.
La Commande info
En plus du système des manuels, des informations concernant des exécutables peuvent être trouvées dans le système info. De l'information détaillée, des exemples et des tutoriels peuvent être absents du système des manuels. Pour cette raison le système info a été créé.
Dans le système info, de multiples pages d'informations concernant un exécutable, appelées nœuds, sont regroupées. La navigation entre nœuds est simple et utilise un système de liens hypertexte.
Afin de faciliter la navigation chaque page contient une entête qui inclut de l'information sur le nœud courant, le nœud parent, le nœud précédent et le nœud suivant. Pour naviguer entre les nœuds il convient d'utiliser les touches suivantes :
| Touch | Fonction |
|---|---|
| n | Nœud suivant. |
| p | Nœud précédent. |
| u | Nœud parent. |
| Espace | Défiler une page vers le bas. |
| Suppr | Défiler une page vers le haut. |
| b | Retour au début du nœud courant. |
| Tab ⇆ | Sélectionner le lien hypertexte suivant. |
| m <lien> | Aller au sous-nœud spécifié. En appuyant sur [Tab], on obtient la liste de tous les sous-nœuds. |
| ↵ Entrée | Suivre le lien hypertexte courant. Un lien hypertexte commence avec un astérisque et se termine avec le caractère :. |
| q | Quitter le système info. |
Pour accéder au premier nœud, utilisez la commande suivante :
root@debian9:~# 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.
Options de la commande
Les options de cette commande sont :
root@debian9:~# 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/
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Copyright © 2019 Hugh Norris.<br><br>
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