{"id":978,"date":"2015-01-29T21:18:29","date_gmt":"2015-01-29T21:18:29","guid":{"rendered":"https:\/\/stevepedwards.today\/DebianAdmin\/?p=978"},"modified":"2015-01-29T21:18:29","modified_gmt":"2015-01-29T21:18:29","slug":"linux-commands-packages-how-many-and-what-for","status":"publish","type":"post","link":"https:\/\/stevepedwards.today\/DebianAdmin\/linux-commands-packages-how-many-and-what-for\/","title":{"rendered":"Linux Commands + Packages – How Many, and What For?"},"content":{"rendered":"
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Linux has thousands of applications and programmes available to it, some are fundamental to its operation as part of the base system, and most are optional additions that can be added as required by the user. So how many are there and how can you find out what each does or what it depends on etc?<\/p>\n

There are projects such as the Linux Documentation Project:<\/p>\n

https:\/\/wiki.tldp.org\/FrontPage<\/span><\/a><\/p>\n

whose aim is to provide info on the system and many Apps etc. but you can find info on your own system using the man command, e.g.<\/p>\n

man\u00a0a2enmod<\/span><\/p>\n

A2ENMOD(8) A2ENMOD(8)<\/span><\/p>\n

NAME<\/span>
\n a2enmod, a2dismod - enable or disable an apache2 module<\/span><\/p>\n

SYNOPSIS<\/span>
\n a2enmod [module]<\/span><\/p>\n

a2dismod [module]<\/span><\/p>\n

DESCRIPTION<\/span>
\n This manual page documents briefly the a2enmod and a2dismod commands.<\/span><\/p>\n

a2enmod is a script that enables the specified module within the apache2 con\u00c3:<\/span>
\n figuration....<\/span><\/p>\n

or by:<\/p>\n

stevee@raspberrypi ~ $ apt-cache<\/span>
\napt 0.9.7.9 for armhf compiled on Oct 28 2014 23:08:37<\/span>
\nUsage: apt-cache [options] command<\/span>
\n apt-cache [options] showpkg pkg1 [pkg2 ...]<\/span>
\n apt-cache [options] showsrc pkg1 [pkg2 ...]<\/span><\/p>\n

apt-cache is a low-level tool used to query information<\/span>
\nfrom APT's binary cache files<\/span><\/p>\n

Commands:<\/span>
\n gencaches - Build both the package and source cache<\/span>
\n showpkg - Show some general information for a single package<\/span>
\n showsrc - Show source records<\/span>
\n stats - Show some basic statistics<\/span>
\ndump - Show the entire file in a terse form<\/span>
\n dumpavail - Print an available file to stdout<\/span>
\n unmet - Show unmet dependencies<\/span>
\n search - Search the package list for a regex pattern<\/span>
\n show - Show a readable record for the package<\/span>
\n depends - Show raw dependency information for a package<\/span>
\n rdepends - Show reverse dependency information for a package<\/span>
\n pkgnames - List the names of all packages in the system<\/span>
\n dotty - Generate package graphs for GraphViz<\/span>
\n xvcg - Generate package graphs for xvcg<\/span>
\n policy - Show policy settings<\/span><\/p>\n

Options:<\/span>
\n -h This help text.<\/span>
\n -p=? The package cache.<\/span>
\n -s=? The source cache.<\/span>
\n -q Disable progress indicator.<\/span>
\n -i Show only important deps for the unmet command.<\/span>
\n -c=? Read this configuration file<\/span>
\n -o=? Set an arbitrary configuration option, eg -o dir::cache=\/tmp<\/span>
\nSee the apt-cache(8) and apt.conf(5) manual pages for more information.<\/span><\/p>\n

For example:<\/p>\n

stevee@raspberrypi ~ $ apt-cache showpkg ntop<\/span>
\nPackage: ntop<\/span>
\nVersions:<\/span>
\n3:4.99.3+ndpi5517+dfsg3-1 (\/var\/lib\/apt\/lists\/mirrordirector.raspbian.org_raspbian_dists_wheezy_main_binary-armhf_Packages) (\/var\/lib\/dpkg\/status)<\/span>
\n Description Language:<\/span>
\n File: \/var\/lib\/apt\/lists\/mirrordirector.raspbian.org_raspbian_dists_wheezy_main_binary-armhf_Packages<\/span>
\n MD5: 8d7e6637c6b740b203a76421995fd582<\/span><\/p>\n

Reverse Depends:<\/span>
\n ntop-dbg,ntop 3:4.99.3+ndpi5517+dfsg3-1<\/span>
\n ntop-data,ntop 3:4.0<\/span>
\n ntop-data,ntop 3:4.0<\/span>
\n ntop-data,ntop 3:4.99.3+ndpi5517+dfsg3-1<\/span>
\n harden-nids,ntop<\/span>
\nDependencies:<\/span>
\n3:4.99.3+ndpi5517+dfsg3-1 - libc6 (2 2.13-28) libgcc1 (2 1:4.4.0) libgdbm3 (2 1.8.3) libgeoip1 (2 1.4.8+dfsg) libpcap0.8 (2 0.9.8) libpython2.7 (2 2.7) librrd4 (2 1.3.0) zlib1g (2 1:1.1.4) debconf (18 0.5) debconf-2.0 (0 (null)) ntop-data (5 3:4.99.3+ndpi5517+dfsg3-1) python-mako (0 (null)) net-tools (0 (null)) adduser (0 (null)) passwd (0 (null)) graphviz (0 (null)) gsfonts (0 (null))<\/span>
\nProvides:<\/span>
\n3:4.99.3+ndpi5517+dfsg3-1 -<\/span>
\nReverse Provides:<\/span><\/p>\n

or by using the \"--help\" switch appended to many commands to give a summarised list of switch options, in many cases:<\/p>\n

stevee@raspberrypi ~ $ htop --help<\/span>
\nhtop 1.0.1 - (C) 2004-2011 Hisham Muhammad<\/span>
\nReleased under the GNU GPL.<\/span><\/p>\n

-C --no-color Use a monochrome color scheme<\/span>
\n-d --delay=DELAY Set the delay between updates, in tenths of seconds<\/span>
\n-h --help Print this help screen<\/span>
\n-s --sort-key=COLUMN Sort by COLUMN (try --sort-key=help for a list)<\/span>
\n-u --user=USERNAME Show only processes of a given user<\/span>
\n-v --version Print version info<\/span><\/p>\n

Long options may be passed with a single dash.<\/span><\/p>\n

Press F1 inside htop for online help.<\/span>
\nSee 'man htop' for more information.<\/span><\/p>\n

So how many binaries are there and what are they?<\/p>\n

A list of programs can be output, sorted alphabetically and read page by page using the compgen -c command:<\/p>\n

compgen -c | sort | less<\/span><\/p>\n

:<\/span>
\n!<\/span>
\n.<\/span>
\n[<\/span>
\n[<\/span>
\n[[<\/span>
\n]]<\/span>
\n{<\/span>
\n}<\/span>
\n2to3<\/span>
\n2to3-2.7<\/span>
\n2to3-3.2<\/span>
\n411toppm<\/span>
\na2dismod<\/span>
\na2dissite<\/span>
\na2enmod<\/span>
\na2ensite<\/span>
\na2p<\/span>
\nab<\/span>
\naccept<\/span>
\naccessdb<\/span>
\naconnect<\/span>
\naddftinfo<\/span>
\naddgroup<\/span>
\naddpart<\/span>
\naddr2line<\/span>
\nadd-shell<\/span>
\nadduser<\/span><\/p>\n

You could then try the man cmd against these to find what they do - if there is a man page written for it e.g.<\/p>\n

man [<\/span><\/p>\n

TEST(1) User Commands TEST(1)<\/span><\/p>\n

NAME<\/span>
\n test - check file types and compare values<\/span><\/p>\n

SYNOPSIS<\/span>
\n test EXPRESSION<\/span>
\n test<\/span><\/p>\n

[ EXPRESSION ]<\/span>
\n [ ]<\/span>
\n [ OPTION.....<\/span><\/p>\n

To find how many there are, use the line listing of word count, wc:<\/p>\n

root@raspberrypi:\/home\/stevee# compgen -c | sort | wc -l<\/span>
\n1922<\/span><\/p>\n

About\u00a02000 base function system type binary commands for this Linux flavour and release version.<\/p>\n

What about the packages available for this flavour? The can be listed from a-z using:<\/p>\n

dpkg --list<\/span><\/p>\n

Desired=Unknown\/Install\/Remove\/Purge\/Hold<\/span>
\n| Status=Not\/Inst\/Conf-files\/Unpacked\/halF-conf\/Half-inst\/trig-aWait\/Trig-pend<\/span>
\n|\/ Err?=(none)\/Reinst-required (Status,Err: uppercase=bad)<\/span>
\n||\/ Name Version Architecture Description<\/span>
\n+++-=========-===========-============-====================<\/span>
\nii adduser 3.113+nmu3 all add and remove users and groups<\/span>
\nii alsa-base 1.0.25+3~deb7u1 all ALSA driver configuration files<\/span>
\nii alsa-utils 1.0.25-4 armhf Utilities for configuring and using ALSA...<\/span><\/p>\n

I assume the total packages installed so far must be:<\/p>\n

root@raspberrypi:\/home\/stevee# dpkg -l | wc -l<\/span>
\n903<\/span><\/p>\n

Why? Well, the total packages available for this flavour is given by:<\/p>\n

apt-cache -h<\/span><\/p>\n

pkgnames - List the names of all packages in the system<\/span><\/p>\n

apt-cache pkgnames<\/span><\/p>\n

This gives a scrolling list about 40,000 lines long, so may take some seconds, but counted with wc -l, gives:<\/p>\n

root@raspberrypi:\/home\/stevee# apt-cache pkgnames | wc -l<\/span>
\n37503<\/span><\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

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Linux has thousands of applications and programmes available to it, some are fundamental to its operation as part of the base system, and most are optional additions that can be added as required by the user. So how many are there and how can you find out what each does or what it depends on ...\u00a0 Linux Commands + Packages – How Many, and What For?<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-978","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"a3_pvc":{"activated":true,"total_views":2,"today_views":0},"_links":{"self":[{"href":"https:\/\/stevepedwards.today\/DebianAdmin\/wp-json\/wp\/v2\/posts\/978","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/stevepedwards.today\/DebianAdmin\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/stevepedwards.today\/DebianAdmin\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/stevepedwards.today\/DebianAdmin\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/stevepedwards.today\/DebianAdmin\/wp-json\/wp\/v2\/comments?post=978"}],"version-history":[{"count":0,"href":"https:\/\/stevepedwards.today\/DebianAdmin\/wp-json\/wp\/v2\/posts\/978\/revisions"}],"wp:attachment":[{"href":"https:\/\/stevepedwards.today\/DebianAdmin\/wp-json\/wp\/v2\/media?parent=978"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/stevepedwards.today\/DebianAdmin\/wp-json\/wp\/v2\/categories?post=978"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/stevepedwards.today\/DebianAdmin\/wp-json\/wp\/v2\/tags?post=978"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}