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{{Article summary start}}
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[[it:Core utilities]]
{{Article summary text|Tips and tricks related to so-called ''core'' utilities on a GNU/Linux system.}}
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[[ko:Core utilities]]
{{Article summary wiki|Bash}}: improved Bourne shell, Linux standard
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[[pt:Core utilities]]
{{Article summary wiki|Zsh}}: improved Bourne/C shell, very good as interactive shell
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{{Article summary wiki|General Recommendations}}
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{{Article summary wiki|GNU Project}}
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{{Related articles start}}
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{{Related|Command-line shell}}
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{{Related|Users and groups}}
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{{Related|systemd}}
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{{Related|pacman}}
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{{Related|General recommendations}}
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{{Related articles end}}
  
This article deals with so-called ''core'' utilities on a GNU/Linux system, such as ''less'', ''ls'', and ''grep''. The scope of this article includes, but is not limited to, those utilities included with the GNU {{Pkg|coreutils}} package. What follows are various tips and tricks and other helpful information related to these utilities.
+
''Core utilities'' are the basic, fundamental tools of a [[GNU]]/[[Linux]] system. On Arch Linux they are found in the [[base group]]. This article provides an incomplete overview of them, links their documentation and describes useful alternatives. The scope of this article includes, but is not limited to, the [https://www.gnu.org/software/coreutils/coreutils.html GNU coreutils]. Most core utilities are traditional [[Wikipedia:Unix|Unix]] tools (see [[Heirloom]]) and many were standardized by [[Wikipedia:POSIX|POSIX]] but have been developed further to provide more features.
  
== cat ==
+
Most command-line interfaces are documented in [[man page]]s, utilities by the [[GNU Project]] are documented in [[Info manual]]s, some [[shell]]s provide a {{ic|help}} command for shell builtin commands. Additionally most utilities print their usage when run with the {{ic|--help}} flag.
  
[[Wikipedia:cat_(Unix)|cat]] (''catenate'') is a standard Unix utility that concatenates and lists files.
+
== Essentials ==
  
* As ''cat'' is not a shell built-in, in many occasions you may find more convenient to use a [[wikipedia:Redirection (computing)|redirection]], for example in scripts, or if you care a lot about performance. In fact {{ic|< ''file''}} does the same of {{ic|cat ''file''}}.
+
The following table lists some important utilities which Arch Linux users should be familiar with. See also {{man|1|intro}}.
  
* To append multiple lines to a file a construct like this one is used:
+
{| class=wikitable
 +
! Package !! Utility !! Description !! Documentation !! Alternatives
 +
|-
 +
| shell built-ins || cd || change directory || {{man|1p|cd}}
 +
|-
 +
|rowspan=12| GNU {{Pkg|coreutils}}
 +
| ls || list directory || {{man|1|ls}}, [https://www.gnu.org/software/coreutils/manual/html_node/ls-invocation.html info] || {{Pkg|exa}}, {{Pkg|tree}}
 +
|-
 +
| cat || concatenate files to stdout || {{man|1|cat}}, [https://www.gnu.org/software/coreutils/manual/html_node/cat-invocation.html info] || {{man|1|tac}}
 +
|-
 +
| mkdir || make directory || {{man|1|mkdir}}, [https://www.gnu.org/software/coreutils/manual/html_node/mkdir-invocation.html info]
 +
|-
 +
| rmdir || remove empty directory || {{man|1|rmdir}}, [https://www.gnu.org/software/coreutils/manual/html_node/rmdir-invocation.html info]
 +
|-
 +
| rm || remove files or directories || {{man|1|rm}}, [https://www.gnu.org/software/coreutils/manual/html_node/rm-invocation.html info] || [[shred]]
 +
|-
 +
| cp || copy files or directories || {{man|1|cp}}, [https://www.gnu.org/software/coreutils/manual/html_node/cp-invocation.html info]
 +
|-
 +
| mv || move files or directories || {{man|1|mv}}, [https://www.gnu.org/software/coreutils/manual/html_node/mv-invocation.html info]
 +
|-
 +
| ln || make hard or symbolic links || {{man|1|ln}}, [https://www.gnu.org/software/coreutils/manual/html_node/ln-invocation.html info]
 +
|-
 +
| [[chown]] || change file owner and group || {{man|1|chown}}, [https://www.gnu.org/software/coreutils/manual/html_node/chown-invocation.html info] || {{man|1|chgrp}}
 +
|-
 +
| [[chmod]] || change file permissions || {{man|1|chmod}}, [https://www.gnu.org/software/coreutils/manual/html_node/chmod-invocation.html info]
 +
|-
 +
| [[dd]] || convert and copy a file || {{man|1|dd}}, [https://www.gnu.org/software/coreutils/manual/html_node/dd-invocation.html info]
 +
|-
 +
| df || report file system disk space usage || {{man|1|df}}, [https://www.gnu.org/software/coreutils/manual/html_node/df-invocation.html info]
 +
|-
 +
| GNU {{Pkg|tar}} || [[tar]] || tar archiver || {{man|1|tar}}, [https://www.gnu.org/software/tar/manual/html_chapter/index.html info] || [[archiver]]s
 +
|-
 +
| GNU {{Pkg|less}} || less || terminal pager || {{man|1|less}} || [[terminal pager]]s
 +
|-
 +
| GNU {{Pkg|findutils}} || find || search files or directories || {{man|1|find}}, [https://www.gnu.org/software/findutils/manual/html_node/find_html/index.html info], [[GregsWiki:UsingFind|GregsWiki]] || [[#find alternatives]]
 +
|-
 +
| GNU {{Pkg|diffutils}} || diff || compare files line by line || {{man|1|diff}}, [https://www.gnu.org/software/diffutils/manual/html_node/Invoking-diff.html info] || [[#diff alternatives]]
 +
|-
 +
| GNU {{Pkg|grep}} || grep || print lines matching a pattern || {{man|1|grep}}, [https://www.gnu.org/software/grep/manual/html_node/index.html info] || [[#grep alternatives]]
 +
|-
 +
| GNU {{Pkg|sed}} || sed || stream editor || {{man|1|sed}}, [https://www.gnu.org/software/sed/manual/html_node/index.html info], [http://sed.sourceforge.net/sed1line.txt one-liners]
 +
|-
 +
| GNU {{Pkg|gawk}} || awk || pattern scanning and processing language || {{man|1|gawk}}, [https://www.gnu.org/software/gawk/manual/html_node/index.html info] || {{Pkg|nawk}}, {{AUR|mawk}}
 +
|-
 +
|rowspan=6| {{Pkg|util-linux}}
 +
| [[Wikipedia:dmesg|dmesg]] || print or control the kernel ring buffer || {{man|1|dmesg}} || [[systemd journal]]
 +
|-
 +
| [[lsblk]] || list block devices || {{man|8|lsblk}}
 +
|-
 +
| [[mount]] || mount a filesystem || {{man|8|mount}}
 +
|-
 +
| [[umount]] || unmount a filesystem || {{man|8|umount}}
 +
|-
 +
| [[su]] || substitute user || {{man|1|su}} || [[sudo]]
 +
|-
 +
| kill || terminate a process || {{man|1|kill}} || {{man|1|pkill}}, {{man|1|killall}}
 +
|-
 +
|rowspan=3| {{Pkg|procps-ng}}
 +
| pgrep || look up processes by name or attributes || {{man|1|pgrep}} || {{man|1|pidof}}
 +
|-
 +
| ps || show information about processes || {{man|1|ps}} ||rowspan=2| {{man|1|top}}, {{Pkg|htop}}
 +
|-
 +
| free || display amount of free and used memory || {{man|1|free}}
 +
|}
  
{{bc|
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=== Preventing data loss ===
$ cat << EOF >> ''path/file''
 
''first line''
 
...
 
''last line''
 
EOF
 
}}
 
  
* If you need to cat file lines in reverse order, there is a utility called [[Wikipedia:tac (Unix)|tac]] (''cat'' reversed).
+
rm, mv, cp and shell redirections happily delete or overwrite files without asking. rm, mv and cp all support the {{ic|-i}} flag to prompt the user before every removal / overwrite. Some users like to enable the {{ic|-i}} flag by default using [[alias]]es. Such shell settings are however dangerous because you get used to them, resulting in potential data loss when you use another system or user that does not have them. The best way to prevent data loss is to do [[backup]]s.
  
== grep ==
+
== Nonessentials ==
  
[[Wikipedia:grep|grep]] (from [[Wikipedia:ed|ed]]'s ''g/re/p'', ''global/regular expression/print'') is a command line text search utility originally written for Unix. The ''grep'' command searches files or standard input globally for lines matching a given regular expression, and prints them to the program's standard output.
+
This table lists core utilities that often come in handy.
* Remember that ''grep'' handles files, so a construct like {{ic|$ cat ''file'' <nowiki>|</nowiki> grep ''pattern''}} is replaceable with {{ic|$ grep ''pattern'' ''file''}}
 
  
* If you have to grep VCS source code, there is an optimized utility written in Perl and called {{Pkg|ack}}. See the [http://beyondgrep.com/ official web site].
+
{| class=wikitable
 +
! Package !! Utility !! Description !! Documentation !! Alternatives
 +
|-
 +
|rowspan=3| shell built-ins
 +
| alias || define or display aliases || {{man|1p|alias}}
 +
|-
 +
| type || print the type of a command || {{man|1p|type}} || {{man|1|which}}
 +
|-
 +
| time || time a command || {{man|1p|time}}
 +
|-
 +
|rowspan=11| GNU {{Pkg|coreutils}}
 +
| tee || read stdin and write to stdout and files || {{man|1|tee}}, [https://www.gnu.org/software/coreutils/manual/html_node/tee-invocation.html info]
 +
|-
 +
| mktemp || make a temporary file or directory || {{man|1|mktemp}}, [https://www.gnu.org/software/coreutils/manual/html_node/mktemp-invocation.html info]
 +
|-
 +
| cut || print selected parts of lines || {{man|1|cut}}, [https://www.gnu.org/software/coreutils/manual/html_node/cut-invocation.html info]
 +
|-
 +
| tr || translate or delete characters || {{man|1|tr}}, [https://www.gnu.org/software/coreutils/manual/html_node/tr-invocation.html info]
 +
|-
 +
| od || dump files in octal and other formats || {{man|1|od}}, [https://www.gnu.org/software/coreutils/manual/html_node/od-invocation.html info] || {{man|1|hexdump}}, [[vim]]'s {{man|1|xxd}}
 +
|-
 +
| sort || sort lines || {{man|1|sort}}, [https://www.gnu.org/software/coreutils/manual/html_node/sort-invocation.html info]
 +
|-
 +
| uniq || report or omit repeated lines || {{man|1|uniq}}, [https://www.gnu.org/software/coreutils/manual/html_node/uniq-invocation.html info]
 +
|-
 +
| comm || compare two sorted files line by line || {{man|1|comm}}, [https://www.gnu.org/software/coreutils/manual/html_node/comm-invocation.html info]
 +
|-
 +
| head || output the first part of files || {{man|1|head}}, [https://www.gnu.org/software/coreutils/manual/html_node/head-invocation.html info]
 +
|-
 +
| tail || output the last part of files, or follow files || {{man|1|tail}}, [https://www.gnu.org/software/coreutils/manual/html_node/tail-invocation.html info]
 +
|-
 +
| wc || print newline, word and byte count || {{man|1|wc}}, [https://www.gnu.org/software/coreutils/manual/html_node/wc-invocation.html info]
 +
|-
 +
| GNU {{Pkg|binutils}} || strings || print printable characters in binary files || {{man|1|strings}}, [https://sourceware.org/binutils/docs/binutils/strings.html info]
 +
|-
 +
| GNU {{Pkg|glibc}} || iconv || convert character encodings || {{man|1|iconv}} || {{Pkg|recode}}
 +
|-
 +
| {{Pkg|file}} || file || guess file type || {{man|1|file}}
 +
|}
  
=== Colored output ===
+
The {{Pkg|moreutils}} package provides useful tools like {{man|1|sponge}} that are missing from the GNU coreutils.
  
Beyond aesthetics, ''grep''&#39;s color output is immensely useful for learning [[Wikipedia:regexp|regexp]] and ''grep''&#39;s functionality.
+
== Alternatives ==
  
To use the default colors for ''grep'', write the following entry to your shell configuration file, e.g. if using [[Bash]]:
+
Alternatives to the core utilities in the {{Grp|base}} group are [[BusyBox]], the [[Heirloom|Heirloom Toolchest]], {{Pkg|9base}}, {{AUR|sbase-git}} and {{AUR|ubase-git}}.
{{hc|~/.bashrc|2=alias grep='grep --color=auto'}}
 
Alternatively, you can set the {{ic|GREP_OPTIONS}} [[Environment Variables|environment variable]] bearing in mind this may break some scripts that use ''grep'' [http://brainstorm.ubuntu.com/idea/24141/]:
 
export GREP_OPTIONS='--color=auto'
 
To include file line numbers in the output, add {{ic|-n}}:
 
alias grep='grep -n --color=auto'
 
  
The environment variable {{ic|GREP_COLORS}} may be used to specify different colors than the defaults.
+
=== find alternatives ===
  
== ifconfig ==
+
* {{App|fd|Simple, fast and user-friendly alternative to find. Ignores hidden and {{ic|.gitignore}}'d files by default.|https://github.com/sharkdp/fd|{{Pkg|fd}}}}
{{Out of date|Rewrite focusing on ''ip''.}}
+
* {{App|fuzzy-find|Fuzzy completion for finding files.|https://github.com/silentbicycle/ff|{{AUR|ff-git}}}}
 +
* {{App|[[mlocate]]|Merging locate/updatedb implementation.|https://pagure.io/mlocate|{{Pkg|mlocate}}}}
  
[[Wikipedia:ifconfig|ifconfig]] (''interface configuration'') is a system administration utility in Unix-like operating systems to configure, control, and query TCP/IP network interface parameters from a command line interface (CLI) or in system configuration scripts.
+
For graphical file searchers, see [[List of applications/Utilities#File searching]].
  
It is deprecated: the alternative is called [[Configuring_Network|ip]].
+
=== diff alternatives ===
  
== less ==
+
{{Expansion|Add {{AUR|icdiff}}.}}
  
[[Wikipedia:less (Unix)|less]] is a terminal pager program used to view the contents of a text file one screen at a time. Whilst similar to other pages such as
+
While {{Pkg|diffutils}} does not provide a word-wise diff, several other programs do:
[[Wikipedia:more (command)|more]] and [[Wikipedia:pg (Unix)|pg]], ''less'' offers a more advanced interface and complete [http://www.greenwoodsoftware.com/less/faq.html feature-set].
 
  
=== Colored output through environment variables ===
+
* [[git]] diff can do a word diff with {{ic|--color-words}}, using {{ic|--no-index}} it can also be used for files outside of Git working trees.
 +
* {{App|dwdiff|A word diff front-end for the diff program; supports colors.|https://os.ghalkes.nl/dwdiff.html|{{Pkg|dwdiff}}}}
 +
* {{App|GNU wdiff|A wordwise implementation of GNU diff; does not support colors.|https://www.gnu.org/software/wdiff/|{{Pkg|wdiff}}}}
 +
* {{App|cwdiff|A GNU wdiff wrapper that colorizes the output.|https://github.com/junghans/cwdiff|{{AUR|cwdiff}}, {{AUR|cwdiff-git}}}}
  
Add the following lines to your shell configuration file:
+
See also [[List of applications/Utilities#Comparison, diff, merge]].
  
{{hc|~/.bashrc|2=
+
=== grep alternatives ===
export LESS=-R
 
export LESS_TERMCAP_me=$(printf '\e[0m')
 
export LESS_TERMCAP_se=$(printf '\e[0m')
 
export LESS_TERMCAP_ue=$(printf '\e[0m')
 
export LESS_TERMCAP_mb=$(printf '\e[1;32m')
 
export LESS_TERMCAP_md=$(printf '\e[1;34m')
 
export LESS_TERMCAP_us=$(printf '\e[1;32m')
 
export LESS_TERMCAP_so=$(printf '\e[1;44;1m')
 
}}
 
  
Change values as you like. References: [[Wikipedia:ANSI_escape_code#Colors|ANSI escape code]].
+
* {{App|mgrep|A multiline grep.|https://sourceforge.net/projects/multiline-grep/|{{AUR|mgrep}}}}
  
=== Colored output through wrappers ===
+
==== Code searchers ====
  
You can enable code syntax coloring in ''less''. First, install {{Pkg|source-highlight}}, then add these lines to your shell configuration file:
+
The following three tools aim to replace grep for code search. They do recursive search by default, skip binary files and respect {{ic|.gitignore}}.
{{hc|~/.bashrc|<nowiki>
 
export LESSOPEN="| /usr/bin/source-highlight-esc.sh %s"
 
export LESS='-R '
 
</nowiki>}}
 
  
Frequent users of the command line interface might want to install {{Pkg|lesspipe}}.
+
* {{App|ack|A Perl-based grep replacement, aimed at programmers with large trees of heterogeneous source code.|https://beyondgrep.com/|{{Pkg|ack}}}}
 +
* {{App|ripgrep (rg)|A search tool that combines the usability of ag with the raw speed of grep.|https://github.com/BurntSushi/ripgrep|{{Pkg|ripgrep}}}}
 +
* {{App|The Silver Searcher (ag)|Code searching tool similar to Ack, but faster.|https://github.com/ggreer/the_silver_searcher|{{Pkg|the_silver_searcher}}}}
  
Users may now list the compressed files inside of an archive using their pager:
+
==== Interactive filters ====
  
{{hc|$ less ''compressed_file''.tar.gz|2=
+
* {{App|[[fzf]]|General-purpose command-line fuzzy finder, powered by find by default.|https://github.com/junegunn/fzf|{{Pkg|fzf}}, {{AUR|fzf-git}}}}
==> use tar_file:contained_file to view a file in the archive
+
* {{App|fzy|A fast, simple fuzzy text selector with an advanced scoring algorithm.|https://github.com/jhawthorn/fzy|{{Pkg|fzy}}, {{AUR|fzy-git}}}}
-rw------- ''username''/''group''  695 2008-01-04 19:24 ''compressed_file''/''content1''
+
* {{App|peco|Simplistic interactive filtering tool.|https://github.com/peco/peco|{{AUR|peco}}, {{AUR|peco-git}}}}
-rw------- ''username''/''group''  43 2007-11-07 11:17 ''compressed_file''/''content2''
+
* {{App|percol|Adds flavor of interactive filtering to the traditional pipe concept of the UNIX shell.|https://github.com/mooz/percol|{{Pkg|percol}}, {{AUR|percol-git}}}}
''compressed_file''.tar.gz (END)
 
}}
 
 
 
''lesspipe'' also grants ''less'' the ability of interfacing with files other than archives, serving as an alternative for the specific command associated for that file-type (such as viewing HTML via {{Pkg|html2text}}).
 
 
 
Re-login after installing ''lesspipe'' in order to activate it, or source {{ic|/etc/profile.d/lesspipe.sh}}.
 
 
 
=== Vim as alternative pager ===
 
 
 
[[Vim]] (''visual editor improved'') has a script to view the content of text files, compressed files, binaries, directories. Add the following line to your shell configuration file to use it as a pager:
 
{{hc|~/.bashrc|2=alias less='/usr/share/vim/vim73/macros/less.sh'}}
 
 
 
== ls ==
 
 
 
[[Wikipedia:ls|ls]] (''list'') is a command to list files in Unix and Unix-like operating systems.
 
 
 
Colored output can be enabled with a simple alias. File {{ic|~/.bashrc}} should already have the following entry copied from {{ic|/etc/skel/.bashrc}}:
 
alias ls='ls --color=auto'
 
The next step will further enhance the colored ''ls'' output; for example, broken (orphan) symlinks will start showing in a red hue. Add the following to your shell configuration file:
 
{{hc|~/.bashrc|eval $(dircolors -b)}}
 
 
 
== man ==
 
 
 
[[Wikipedia:Man page|man]] (''manual page'') is a form of online software documentation usually found on a Unix or Unix-like operating system. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts. See [[Man Pages]].
 
 
 
== mkdir ==
 
 
 
[[Wikipedia:mkdir_(Unix)|mkdir]] (''make directory'') is a command to create directories. To create a directory and its whole hierarchy, {{ic|-p}} switch is used, if not a error is printed. As users are supposed to know what they want, {{ic|-p}} switch may be used as a default.
 
alias mkdir='mkdir -p -v'
 
The {{ic|-v}} switch make it verbose.
 
{{Tip|If you want just a temporary directory a better alternative may be [[Wikipedia:Temporary file|mktemp]] (''make termporary''): {{ic|mktemp -p}}.
 
}}
 
 
 
== mv ==
 
 
 
[[Wikipedia:mv_(Unix)|mv]] (''move'') is a command to move and rename files and directories. It can be very dangerous so it is prudent to limit its scope:
 
alias mv=' timeout 8 mv -iv'
 
This alias suspends ''mv'' after eight seconds, asks confirmation to delete three or more files, lists the operations in progress and does not store itself in the shell history file if the shell is configured to ignore space starting commands.
 
 
 
== rm ==
 
 
 
[[Wikipedia:rm_(Unix)|rm]] (''remove'') is a command to delete files and directories. It can be very dangerous so it is prudent to limit its scope:
 
alias rm=' timeout 3 rm -Iv --one-file-system'
 
This alias suspends ''rm'' after three seconds, asks confirmation to delete three or more files, lists the operations in progress, does not involve more than one file systems and does not store itself in the shell history file if the shell is configured to ignore space starting commands. Substitute {{ic|-I}} with {{ic|-i}} if you prefer to confirm even for one file.
 
 
 
== sed ==
 
 
 
[[Wikipedia:sed|sed]] (''stream editor'') is a Unix utility that parses and transforms text.
 
 
 
Here is a handy [http://sed.sourceforge.net/sed1line.txt list] of ''sed'' one-liners examples.
 
 
 
{{Tip|More powerful alternatives are [[Wikipedia:AWK|AWK]] and even [[Wikipedia:Perl|Perl]] language.}}
 
 
 
== seq ==
 
 
 
'''seq''' (''sequence'') is a utility for generating a sequence of numbers. Shell built-in alternatives are available, so it is good practice to use them as explained on [[Wikipedia:seq|Wikipedia]].
 
 
 
== shred ==
 
 
 
[[Wikipedia:Shred_(Unix)|shred]] is a command to securely delete files and directories. It can be very dangerous so it is prudent to limit its scope:
 
alias shred=' timeout 3 shred -v'
 
This alias suspends ''shred'' after three seconds, lists the operations in progress, and does not store itself in the shell history file if the shell is configured to ignore space starting commands.
 
 
 
== sudo ==
 
 
 
[[Wikipedia:Sudo|Sudo]] (''as superuser do'') is a program for Unix-like computer operating systems that allows users to run programs with the security privileges of another user (normally the superuser, or root). See [[Sudo]].
 
  
 
== See also ==
 
== See also ==
  
* [http://www.reddit.com/r/commandline/comments/19garq/a_sampling_of_coreutils_120/ A sampling of coreutils] [http://www.reddit.com/r/commandline/comments/19ge6v/a_sampling_of_coreutils_2040/ , part 2] [http://www.reddit.com/r/commandline/comments/19j1w3/a_sampling_of_coreutils_4060/ , part 3] - Overview of commands in coreutils
+
* [https://www.gnu.org/software/coreutils/manual/coreutils.html GNU Coreutils documentation]
 +
* [http://pubs.opengroup.org/onlinepubs/9699919799/idx/utilities.html POSIX utilities]

Latest revision as of 15:26, 18 November 2018

Core utilities are the basic, fundamental tools of a GNU/Linux system. On Arch Linux they are found in the base group. This article provides an incomplete overview of them, links their documentation and describes useful alternatives. The scope of this article includes, but is not limited to, the GNU coreutils. Most core utilities are traditional Unix tools (see Heirloom) and many were standardized by POSIX but have been developed further to provide more features.

Most command-line interfaces are documented in man pages, utilities by the GNU Project are documented in Info manuals, some shells provide a help command for shell builtin commands. Additionally most utilities print their usage when run with the --help flag.

Essentials

The following table lists some important utilities which Arch Linux users should be familiar with. See also intro(1).

Package Utility Description Documentation Alternatives
shell built-ins cd change directory cd(1p)
GNU coreutils ls list directory ls(1), info exa, tree
cat concatenate files to stdout cat(1), info tac(1)
mkdir make directory mkdir(1), info
rmdir remove empty directory rmdir(1), info
rm remove files or directories rm(1), info shred
cp copy files or directories cp(1), info
mv move files or directories mv(1), info
ln make hard or symbolic links ln(1), info
chown change file owner and group chown(1), info chgrp(1)
chmod change file permissions chmod(1), info
dd convert and copy a file dd(1), info
df report file system disk space usage df(1), info
GNU tar tar tar archiver tar(1), info archivers
GNU less less terminal pager less(1) terminal pagers
GNU findutils find search files or directories find(1), info, GregsWiki #find alternatives
GNU diffutils diff compare files line by line diff(1), info #diff alternatives
GNU grep grep print lines matching a pattern grep(1), info #grep alternatives
GNU sed sed stream editor sed(1), info, one-liners
GNU gawk awk pattern scanning and processing language gawk(1), info nawk, mawkAUR
util-linux dmesg print or control the kernel ring buffer dmesg(1) systemd journal
lsblk list block devices lsblk(8)
mount mount a filesystem mount(8)
umount unmount a filesystem umount(8)
su substitute user su(1) sudo
kill terminate a process kill(1) pkill(1), killall(1)
procps-ng pgrep look up processes by name or attributes pgrep(1) pidof(1)
ps show information about processes ps(1) top(1), htop
free display amount of free and used memory free(1)

Preventing data loss

rm, mv, cp and shell redirections happily delete or overwrite files without asking. rm, mv and cp all support the -i flag to prompt the user before every removal / overwrite. Some users like to enable the -i flag by default using aliases. Such shell settings are however dangerous because you get used to them, resulting in potential data loss when you use another system or user that does not have them. The best way to prevent data loss is to do backups.

Nonessentials

This table lists core utilities that often come in handy.

Package Utility Description Documentation Alternatives
shell built-ins alias define or display aliases alias(1p)
type print the type of a command type(1p) which(1)
time time a command time(1p)
GNU coreutils tee read stdin and write to stdout and files tee(1), info
mktemp make a temporary file or directory mktemp(1), info
cut print selected parts of lines cut(1), info
tr translate or delete characters tr(1), info
od dump files in octal and other formats od(1), info hexdump(1), vim's xxd(1)
sort sort lines sort(1), info
uniq report or omit repeated lines uniq(1), info
comm compare two sorted files line by line comm(1), info
head output the first part of files head(1), info
tail output the last part of files, or follow files tail(1), info
wc print newline, word and byte count wc(1), info
GNU binutils strings print printable characters in binary files strings(1), info
GNU glibc iconv convert character encodings iconv(1) recode
file file guess file type file(1)

The moreutils package provides useful tools like sponge(1) that are missing from the GNU coreutils.

Alternatives

Alternatives to the core utilities in the base group are BusyBox, the Heirloom Toolchest, 9base, sbase-gitAUR and ubase-gitAUR.

find alternatives

  • fd — Simple, fast and user-friendly alternative to find. Ignores hidden and .gitignore'd files by default.
https://github.com/sharkdp/fd || fd
  • fuzzy-find — Fuzzy completion for finding files.
https://github.com/silentbicycle/ff || ff-gitAUR
  • mlocate — Merging locate/updatedb implementation.
https://pagure.io/mlocate || mlocate

For graphical file searchers, see List of applications/Utilities#File searching.

diff alternatives

Tango-view-fullscreen.pngThis article or section needs expansion.Tango-view-fullscreen.png

Reason: Add icdiffAUR. (Discuss in Talk:Core utilities#)

While diffutils does not provide a word-wise diff, several other programs do:

  • git diff can do a word diff with --color-words, using --no-index it can also be used for files outside of Git working trees.
  • dwdiff — A word diff front-end for the diff program; supports colors.
https://os.ghalkes.nl/dwdiff.html || dwdiff
  • GNU wdiff — A wordwise implementation of GNU diff; does not support colors.
https://www.gnu.org/software/wdiff/ || wdiff
  • cwdiff — A GNU wdiff wrapper that colorizes the output.
https://github.com/junghans/cwdiff || cwdiffAUR, cwdiff-gitAUR

See also List of applications/Utilities#Comparison, diff, merge.

grep alternatives

  • mgrep — A multiline grep.
https://sourceforge.net/projects/multiline-grep/ || mgrepAUR

Code searchers

The following three tools aim to replace grep for code search. They do recursive search by default, skip binary files and respect .gitignore.

  • ack — A Perl-based grep replacement, aimed at programmers with large trees of heterogeneous source code.
https://beyondgrep.com/ || ack
  • ripgrep (rg) — A search tool that combines the usability of ag with the raw speed of grep.
https://github.com/BurntSushi/ripgrep || ripgrep
  • The Silver Searcher (ag) — Code searching tool similar to Ack, but faster.
https://github.com/ggreer/the_silver_searcher || the_silver_searcher

Interactive filters

  • fzf — General-purpose command-line fuzzy finder, powered by find by default.
https://github.com/junegunn/fzf || fzf, fzf-gitAUR
  • fzy — A fast, simple fuzzy text selector with an advanced scoring algorithm.
https://github.com/jhawthorn/fzy || fzy, fzy-gitAUR
  • peco — Simplistic interactive filtering tool.
https://github.com/peco/peco || pecoAUR, peco-gitAUR
  • percol — Adds flavor of interactive filtering to the traditional pipe concept of the UNIX shell.
https://github.com/mooz/percol || percol, percol-gitAUR

See also