Find Help on Commands in Linux

paul@fullstack:~$ whatis -s "1" whatis man whatis (1) - display one-line manual page descriptions man (1) - an interface to the on-line reference manuals

paul@fullstack:~$ # command -options(s) argument(s) paul@fullstack:~$ whatis whatis man whatis (1) - display one-line manual page descriptions man (1) - an interface to the on-line reference manuals man (7) - macros to format man pages paul@fullstack:~$ clear

paul@fullstack:~$ man man

MAN(1) Manual pager utils MAN(1) NAME man - an interface to the on-line reference manuals SYNOPSIS man [-C file] [-d] [-D] [--warnings[=warnings]] [-R encoding] [-L locale] [-m sys tem[,...]] [-M path] [-S list] [-e extension] [-i|-I] [--regex|--wildcard] [--names-only] [-a] [-u] [--no-subpages] [-P pager] [-r prompt] [-7] [-E encoding] [--no-hyphenation] [--no-justification] [-p string] [-t] [-T[device]] [-H[browser]] [-X[dpi]] [-Z] [[section] page ...] ... man -k [apropos options] regexp ... man -K [-w|-W] [-S list] [-i|-I] [--regex] [section] term ... man -f [whatis options] page ... man -l [-C file] [-d] [-D] [--warnings[=warnings]] [-R encoding] [-L locale] [-P pager] [-r prompt] [-7] [-E encoding] [-p string] [-t] [-T[device]] [-H[browser]] [-X[dpi]] [-Z] file ... man -w|-W [-C file] [-d] [-D] page ... man -c [-C file] [-d] [-D] page ... man [-?V] DESCRIPTION man is the system's manual pager. Each page argument given to man is normally the name of a program, utility or function. The manual page associated with each of these arguments is then found and displayed. A section, if provided, will direct man to look only in that section of the manual. The default action is to search in all of the available sections following a pre-defined order ("1 n l 8 3 2 3posix 3pm 3perl 5 4 9 6 7" by default, unless overridden by the SECTION directive in /etc/man path.config), and to show only the first page found, even if page exists in several sections. The table below shows the section numbers of the manual followed by the types of pages they contain. 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] 2.7.0.2 2014-09-28 MAN(1)

clear(1) General Commands Manual clear(1) NAME clear - clear the terminal screen SYNOPSIS clear DESCRIPTION clear clears your screen if this is possible, including its scrollback buffer (if the extended "E3" capability is defined). clear looks in the environment for the terminal type and then in the terminfo database to determine how to clear the screen. clear ignores any command-line parameters that may be present. SEE ALSO tput(1), terminfo(5) This describes ncurses version 5.9 (patch 20140913). clear(1)

paul@fullstack:~$ man ls

LS(1) User Commands LS(1) NAME ls - list directory contents SYNOPSIS ls [OPTION]... [FILE]... DESCRIPTION List information about the FILEs (the current directory by default). Sort entries alphabetically if none of -cftuvSUX nor --sort is specified. Mandatory arguments to long options are mandatory for short options too. -a, --all do not ignore entries starting with . -A, --almost-all do not list implied . and .. --author with -l, print the author of each file -b, --escape print C-style escapes for nongraphic characters --block-size=SIZE scale sizes by SIZE before printing them; e.g., '--block-size=M' prints sizes in units of 1,048,576 bytes; see SIZE format below -B, --ignore-backups do not list implied entries ending with ~ -c with -lt: sort by, and show, ctime (time of last modification of file status information); with -l: show ctime and sort by name; otherwise: sort by ctime, newest first -C list entries by columns --color[=WHEN] colorize the output; WHEN can be 'never', 'auto', or 'always' (the default); more info below -d, --directory list directories themselves, not their contents -D, --dired generate output designed for Emacs' dired mode -f do not sort, enable -aU, disable -ls --color -F, --classify append indicator (one of */=>@|) to entries --file-type likewise, except do not append '*' --format=WORD across -x, commas -m, horizontal -x, long -l, single-column -1, verbose -l, vertical -C --full-time like -l --time-style=full-iso -g like -l, but do not list owner --group-directories-first group directories before files; can be augmented with a --sort option, but any use of --sort=none (-U) dis‐ ables grouping -G, --no-group in a long listing, don't print group names -h, --human-readable with -l and/or -s, print human readable sizes (e.g., 1K 234M 2G) --si likewise, but use powers of 1000 not 1024 -H, --dereference-command-line follow symbolic links listed on the command line --dereference-command-line-symlink-to-dir follow each command line symbolic link that points to a directory --hide=PATTERN do not list implied entries matching shell PATTERN (overridden by -a or -A) --indicator-style=WORD append indicator with style WORD to entry names: none (default), slash (-p), file-type (--file-type), classify (-F) -i, --inode print the index number of each file -I, --ignore=PATTERN do not list implied entries matching shell PATTERN -k, --kibibytes default to 1024-byte blocks for disk usage -l use a long listing format -L, --dereference when showing file information for a symbolic link, show information for the file the link references rather than for the link itself -m fill width with a comma separated list of entries -n, --numeric-uid-gid like -l, but list numeric user and group IDs -N, --literal print raw entry names (don't treat e.g. control characters specially) -o like -l, but do not list group information -p, --indicator-style=slash append / indicator to directories -q, --hide-control-chars print ? instead of nongraphic characters --show-control-chars show nongraphic characters as-is (the default, unless program is 'ls' and output is a terminal) -Q, --quote-name enclose entry names in double quotes --quoting-style=WORD use quoting style WORD for entry names: literal, locale, shell, shell-always, c, escape -r, --reverse reverse order while sorting -R, --recursive list subdirectories recursively -s, --size print the allocated size of each file, in blocks -S sort by file size --sort=WORD sort by WORD instead of name: none (-U), size (-S), time (-t), version (-v), extension (-X) --time=WORD with -l, show time as WORD instead of default modification time: atime or access or use (-u) ctime or status (-c); also use specified time as sort key if --sort=time --time-style=STYLE with -l, show times using style STYLE: full-iso, long-iso, iso, locale, or +FORMAT; FORMAT is interpreted like in 'date'; if FORMAT is FORMAT1<new line>FORMAT2, then FORMAT1 applies to non-recent files and FORMAT2 to recent files; if STYLE is prefixed with 'posix-', STYLE takes effect only outside the POSIX locale -t sort by modification time, newest first -T, --tabsize=COLS assume tab stops at each COLS instead of 8 -u with -lt: sort by, and show, access time; with -l: show access time and sort by name; otherwise: sort by access time -U do not sort; list entries in directory order -v natural sort of (version) numbers within text -w, --width=COLS assume screen width instead of current value -x list entries by lines instead of by columns -X sort alphabetically by entry extension -Z, --context print any security context of each file -1 list one file per line --help display this help and exit --version output version information and exit The SIZE argument is an integer and optional unit (example: 10K is 10*1024). Units are K,M,G,T,P,E,Z,Y (powers of 1024) or KB,MB,... (powers of 1000). Using color to distinguish file types is disabled both by default and with --color=never. With --color=auto, ls emits color codes only when standard output is connected to a terminal. The LS_COLORS environment variable can change the set tings. Use the dircolors command to set it. Exit status: 0 if OK, 1 if minor problems (e.g., cannot access subdirectory), 2 if serious trouble (e.g., cannot access command-line argument). AUTHOR Written by Richard M. Stallman and David MacKenzie. REPORTING BUGS GNU coreutils online help: <http://www.gnu.org/software/coreutils/> Report ls translation bugs to <http://translationproject.org/team/> COPYRIGHT Copyright © 2014 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 WAR‐ RANTY, to the extent permitted by law. SEE ALSO Full documentation at: <http://www.gnu.org/software/coreutils/ls> or available locally via: info '(coreutils) ls invocation' GNU coreutils 8.23 March 2015 LS(1)

paul@fullstack:~$ man info

INFO(1) User Commands INFO(1) NAME info - read Info documents SYNOPSIS info [OPTION]... [MENU-ITEM...] DESCRIPTION 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 REPORTING BUGS 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/ COPYRIGHT Copyright © 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 WAR RANTY, to the extent permitted by law. SEE ALSO The full documentation for info is provided by the texinfo-doc-nonfree package as a Texinfo manual. If this package is installed at your site, the command info info should give you access to the complete manual. (Or, if you have Emacs, M-x info will lead to the manual.) info 5.2 December 2014 INFO(1)

paul@fullstack:~$ 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). Editors * nano: (nano). Small and friendly text editor. GNU Utilities (158 lines trimmed)

File: coreutils.info, Node: Top, Next: Introduction, Up: (dir) GNU Coreutils ************* This manual documents version 8.23 of the GNU core utilities, including the standard programs for text and file manipulation. Copyright © 1994-2014 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; wich no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License". * Menu: * Introduction:: Caveats, overview, and authors * Common options:: Common options * Output of entire files:: cat tac nl od base64 * Formatting file contents:: fmt pr fold * Output of parts of files:: head tail split csplit * Summarizing files:: wc sum cksum md5sum sha1sum sha2 * Operating on sorted files:: sort shuf uniq comm ptx tsort * Operating on fields:: cut paste join

File: coreutils.info, Node: Introduction, Next: Common options, Prev: Top, Up: Top 1 Introduction ************** This manual is a work in progress: many sections make no attempt to explain basic concepts in a way suitable for novices. Thus, if you are interested, please get involved in improving this manual. The entire GNU community will benefit. The GNU utilities documented here are mostly compatible with the POSIX standard. Please report bugs to <bug-coreutils&gnu.org>. Remember to include the version number, machine architecture, input files, and any other information needed to reproduce the bug: your input, what you expected, what you got, and why it is wrong. Diffs are welcome, but please include a description of the problem as well, since this is sometimes difficult to infer. *Note (gcc)Bugs::. This manual was originally derived from the Unix man pages in the distributions, which were written by David MacKenzie and updated by Jim Meyering. What you are reading now is the authoritative documentation for these utilities; the man pages are no longer being maintained. The original 'fmt' man page was written by Ross Paterson. François Pinard did the initial conversation to Textinfo format. Karl Berry did the indexing, some reorganization, and editing of the results. Brian Youmans of the Free Software Foundation office staff combined the manuals for textutils, fileutils, and sh-utils to produce the present

paul@fullstack:~$ clear paul@fullstack:~$ type -a nano nano is /usr/bin/nano nano is /bin/nano paul@fullstack:~$ type nano nano is /usr/bin/nano

paul@fullstack:~$ /usr/bin/nano

paul@fullstack:~$ type type type is a shell builtin

paul@fullstack:~$ bash -c help 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 hist> (( expression )) if COMMANDS; then COMMANDS; [ elif C> . filename [arguments] jobs [-lnprs] [jobspec ...] or jobs > : kill [-s sigspec | -n signum | -sigs> [ arg... ] let arg [arg ...] [[ expression ]] local [option] name[=value] ... alias [-p] [name[=value] ... ] logout [n] bg [job_spec ...] mapfile [-n count] [-O origin] [-s c> bind [-lpsvPSVX] [-m keymap] [-f file> 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]...)> read [-ers] [-a array] [-d delim] [-> cd [-L|[-P [-e]] [-@]] [dir] readarray [-n count] [-O origin] [-s> command [-pVv] command [arg ...] readonly [-aAf] [name[=value] ...] o> compgen [-abcdefgjksuv] [-o option] > return [n] complete [-abcdefgjksuv] [-pr] [-DE] > select NAME [in WORDS ... ;] do COMM> compopt [-o|+o option] [-DE] [name ..> set [-abefhkmnptuvxBCHP] [-o option-> continue [n] shift [n] coproc [NAME] command [redirections] shopt [-pqsu] [-o] [optname ...] declare [-aAfFgilnrtux] [-p] [name[=v> source filename [arguments] dirs [-clpv] [+N] [-N] suspend [-f] disown [-h] [-ar] [jobspec ...] test [expr] echo [-neE] [arg ...] time [-p] pipeline enable [-a] [-dnps] [-f filename] [na> times eval [arg ...] trap [-lp] [[arg] signal_spec ...] exec [-cl] [-a name] [command [argume> true exit [n] type [-afptP] name [name ...] export [-fn] [name[=value] ...] or ex> typeset [-aAfFgilrtux] [-p] name[=va> false ulimit [-SHabcdefilmnpqrstuvxT] [lim> fc [-e ename] [-lnr] [first] [last] o> umask [-p] [-S] [mode] fg [job_spec] unalias [-a] name [name ...] for NAME [in WORDS ... ] ; do COMMAND> unset [-f] [-v] [-n] [name ...] for (( exp1; exp2; exp3 )); do COMMAN> until COMMANDS; do COMMANDS; done function name { COMMANDS ; } or name > variables - Names and meanings of so> getopts optstring name [arg] wait [-n] [id ...] hash [-lr] [-p pathname] [-dt] [name > while COMMANDS; do COMMANDS; done help [-dms] [pattern ...] { COMMANDS ; } paul@fullstack:~$ clear

paul@fullstack:~$ 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.

paul@fullstack:~$ ls -1 /usr/share/doc (479 lines trimmed) tasksel tasksel-data task-ssh-server task-web-server tcpd telnet texinfo time traceroute tzdata ucf udev usbutils util-linux util-linux-locales vim vim-common vim-runtime vim-tiny w3m wamerican wget whiptail whois x11-common xauth xdg-user-dirs xkb-data xml-core xz-utils zlib1g

paul@fullstack:~$ less /usr/share/doc/nano/README

GNU nano - an enhanced clone of the Pico text editor. Overview The nano project was started because of a few "problems" with the wonderfully easy-to-use and friendly Pico text editor. First and foremost is its license: the Pine suite does not use the GPL or a GPL-friendly license, and has unclear restrictions on redistribution. Because of this, Pine and Pico are not included with many GNU/Linux distributions. Also, other features (like go to line number or search and replace) were unavailable until recently or require a command line flag. Yuck. nano aims to solve these problems by emulating the functionality of Pico as closely as possible while addressing the problems above and perhaps providing other extra functionality. The nano editor is now an official GNU package. For more information on GNU and the Free Software Foundation, please see http://www.gnu.org/. How to compile and install nano Download the nano source code, then: tar zxvf nano-x.y.z.tar.gz cd nano-x.y.z ./configure make make install It's that simple. Use --prefix with configure to override the default installation directory of /usr/local. If you configured with the "--enable-nanorc" option, after installation you might copy the doc/nanorc.sample to your home directory, rename it to ".nanorc", and then edit it according to your taste. Web Page http://www.nano-editor.org/ Mailing List and Bug Reports Savannah hosts all the nano-related mailing-lists. + info-nano@gnu.org is a very low traffic list used to announce new nano versions or other important information about the project. + help-nano@gnu.org is for those seeking to get help without wanting to hear about the technical details of its development. + nano-devel@gnu.org is the list used by the people that make nano and a general development discussion list, with moderate traffic. To subscribe, send email to nano-<name>-request@gnu.org with a subject of "subscribe", where <name> is the list you want to subscribe to. For general bug reports, send a description of the problem to nano@nano-editor.org or directly to the development list. Current Status GNU nano has reached its third stable milestone, 2.0.x. Development of new features continues in the 2.1.x branch, while 2.0.x versions are dedicated to bug-fixing and polishing. $Id: README 4057 2007-01-29 12:40:48Z dolorous $