Difference between revisions of "Core utilities"

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m (→‎locate: update merge template)
(merge →‎mlocate: with mlocate, merge fd from →‎find alternatives: with file searchers)
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| GNU {{Pkg|less}} || less || terminal pager || {{man|1|less}} || [[terminal pager]]s
 
| GNU {{Pkg|less}} || less || terminal pager || {{man|1|less}} || [[terminal pager]]s
 
|-
 
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| 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]]
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| 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]] || [[List of applications/Utilities#File searching|file searchers]]
 
|-
 
|-
 
| 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|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]]
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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}}.
 
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}}.
 
=== find alternatives ===
 
 
* {{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}}}}
 
 
==== locate ====
 
 
{{Merge|mlocate|Restored the article.}}
 
 
[[Install]] the {{Pkg|mlocate}} package. The package contains an {{ic|updatedb.timer}} unit, which invokes a database update each day. The timer is enabled right after installation, [[start]] it manually if you want to use it before reboot. You can also manually run ''updatedb'' as root at any time. By default, paths such as {{ic|/media}} and {{ic|/mnt}} are ignored, so ''locate'' may not discover files on external devices. See {{man|8|updatedb}} for details.
 
 
The ''locate'' command is a common Unix tool for quickly finding files by name. It offers speed improvements over the [[wikipedia:Find (Unix)|find]] tool by searching a pre-constructed database file, rather than the filesystem directly. The downside of this approach is that changes made since the construction of the database file cannot be detected by ''locate''.
 
 
Before ''locate'' can be used, the database will need to be created. To do this, execute {{ic|updatedb}} as root.
 
 
See also [http://jvns.ca/blog/2015/03/05/how-the-locate-command-works-and-lets-rewrite-it-in-one-minute/ How locate works and rewrite it in one minute].
 
  
 
=== diff alternatives ===
 
=== diff alternatives ===

Revision as of 07:47, 1 September 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. 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 commands print their usage when run with the --help flag.

Essentials

The following table lists important commands, Arch Linux users should be familiar with. See also intro(1).

Package Command 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
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 file searchers
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 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 Command Description Documentation Alternatives
shell built-ins alias define or display aliases alias(1)
type print the type of a command type(1) which(1)
time time a command time(1)
GNU coreutils tee read stdin and write to stdout and files tee(1), info
mktemp make a temporary file or directory mktemp(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.

diff alternatives

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

grep alternatives

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

And then there is also mgrepAUR, a multiline grep.

See also