Getting Help on Linux
Man
The man command is short for manual. It allows you to read the instruction manual for almost every command in Linux and other Unix-like operating systems. Don’t know how to use an application? The first thing to do is to run the man command and then the name of the application.
Below is an excerpt of the manual for the man command itself.
> man man
Man: find all matching manual pages (set MAN_POSIXLY_CORRECT to avoid this) * man (1) man (7mp) man (1p) Man: What manual page do you want? 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 system[,…]] [-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[.section] …] … 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 associ- ated 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 (“0 1 n l 8 3 2 5 4 9 6 7 1x 3x 4x 5x 6x 8x 1bind 3bind 5bind 7bind 8bind 1cn 8cn 1m 1mh 5mh 8mh 1netpbm 3netpbm 5netpbm 0p 1p 3p 3posix 1pgsql 3pgsql 5pgsql 3C++ 8C++ 3blt 3curses 3ncurses 3form 3menu 3db 3gdbm 3f 3gk 3paper 3mm 5mm 3perl 3pm 3pq 3qt 3pub 3readline 1ssl 3ssl 5ssl 7ssl 3t 3tk 3tcl 3tclx 3tix 7l 7nr 8c Cg g s m” by default, unless overridden by the SECTION directive in /etc/manpath.config), and to show only the first page found, even if page exists in several sections.
Why is it that I was given a list of options for the man command? That’s because there are more than one manuals written for “man”. One is the manual application. One is the a macro. Another is a reference in the programmer’s dictionary. Sometimes you have to read them in order to find the one that you need.
Apropos
Apropos searches manuals called manuals. The search function searches both name names and descriptions. If you run something like “apropos the”, you’re going to get pretty much every manual in the English language, so it’s good to keep your search specific. If you need to know how to use x11, then
> apropos apropos
apropos (1) - search the manual page names and descriptions
apropos x11
firefox (1) - a Web browser for X11 derived from the Mozilla browser fonts-config (1) - configures installed X11 fonts. icewm (1) - lightweight X11 window manager pax11publish (1) - PulseAudio X11 Credential Utility pbmtox10bm (1) - convert a PBM image to an X11 bitmap pbmtoxbm (1) - convert a PBM image to an X11 bitmap pnmtoxwd (1) - convert a PNM into an X11 window dump ppmtopuzz (1) - convert a PPM image to an X11 “puzzle” file ppmtoxpm (1) - convert a PPM image to an X11 pixmap start-pulseaudio-x11 (1) - PulseAudio Sound Server X11 Startup Script x11-ssh-askpass (1x) - an X11-based pass-phrase dialog for use with OpenSSH X11::Auth (3pm) - Perl module to read X11 authority files X11::Keysyms (3pm) - Perl module for names of X11 keysyms X11::Protocol (3pm) - Perl module for the X Window System Protocol, version 11 X11::Protocol::Connection (3pm) - Perl module abstract base class for X11 client to server connections X11::Protocol::Connection::FileHandle (3pm) - Perl module base class for FileHandle-based X11 connections X11::Protocol::Connection::INETFH (3pm) - Perl module for FileHandle-based TCP/IP X11 connections X11::Protocol::Connection::INETSocket (3pm) - Perl module for IO::Socket::INET-based X11 connections X11::Protocol::Connection::Socket (3pm) - Perl module base class for IO::Socket-based X11 connections X11::Protocol::Connection::UNIXFH (3pm) - Perl module for FileHandle-based Unix-domain X11 connections X11::Protocol::Connection::UNIXSocket (3pm) - Perl module for IO::Socket::UNIX-based X11 connections X11::Protocol::Ext::BIG_REQUESTS (3pm) - Perl module for the X11 protocol Big Requests extension X11::Protocol::Ext::DPMS (3pm) - Perl module for the X11 Protocol DPMS Extension X11::Protocol::Ext::RENDER (3pm) - Perl module for the X Rendering Extension X11::Protocol::Ext::SHAPE (3pm) - Perl module for the X11 Protocol Nonrectangular Window Shape Extension X11::Protocol::Ext::XC_MISC (3pm) - Perl module for the X11 Protocol XC-MISC Extension X11::Protocol::Ext::XFree86_Misc (3pm) - Perl module for the XFree86 Misc Extension x11perf (1) - X11 server performance test program x11perfcomp (1) - X11 server performance comparison program xbmtopbm (1) - convert an X11 or X10 bitmap to a PBM image xfontsel (1) - point and click selection of X11 font names xkbctrl (1) - get X11 keyboard data according to console keyboard mapname xli (1x) - load images into an X11 window or onto the root window xloadimage (1x) - load images into an X11 window or onto the root window Xmark (1) - summarize x11perf results Xorg (1) - X11R7 X server xpmtoppm (1) - convert an X11 pixmap to a PPM image xrestop (1) - monitor server resources used by X11 clients xwdtopnm (1) - convert an X11 or X10 window dump file to a PNM image
Whatis
Whatis gives just a brief description of what a command does.
> whatis whatis whatis (1) - display one-line manual page descriptions
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