Difference between revisions of "Core utilities"

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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 {{Package Official|coreutils}} package. What follows are various tips and tricks and other helpful information related to these utilities. If sections grow too detailed, please split into separate articles.
 
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 {{Package Official|coreutils}} package. What follows are various tips and tricks and other helpful information related to these utilities. If sections grow too detailed, please split into separate articles.
 
==alias==
 
[[Wikipedia:alias|alias]] is a command in various shells, such as [[Bash]], which enables a replacement of a word with another string. It is often used for abbreviating a system command, or for adding default arguments to a regularly used command.
 
 
Personal aliases are preferably stored in {{Filename|~/.bashrc}}, and system-wide aliases (which affect all users) belong in {{Filename|/etc/bash.bashrc}}.
 
 
An example excerpt from {{Filename|~/.bashrc}} covering several time-saving aliases:
 
{{File
 
|name=~/.bashrc
 
|content=<nowiki>
 
# modified commands
 
alias diff='colordiff'              # requires colordiff package
 
alias grep='grep --color=auto'
 
alias more='less'
 
alias df='df -h'
 
alias du='du -c -h'
 
alias mkdir='mkdir -p -v'
 
alias nano='nano -w'
 
alias ping='ping -c 5'
 
alias ..='cd ..'
 
 
# new commands
 
alias da='date "+%A, %B %d, %Y [%T]"'
 
alias du1='du --max-depth=1'
 
alias hist='history | grep $1'      # requires an argument
 
alias openports='netstat --all --numeric --programs --inet --inet6'
 
alias pg='ps -Af | grep $1'        # requires an argument (note: /usr/bin/pg is installed by the util-linux package; maybe a different alias name should be used)
 
 
# privileged access
 
if [ $UID -ne 0 ]; then
 
    alias sudo='sudo '
 
    alias scat='sudo cat'
 
    alias svim='sudo vim'
 
    alias root='sudo su'
 
    alias reboot='sudo reboot'
 
    alias halt='sudo halt'
 
    alias update='sudo pacman -Su'
 
    alias netcfg='sudo netcfg2'
 
fi
 
 
# ls
 
alias ls='ls -hF --color=auto'
 
alias lr='ls -R'                    # recursive ls
 
alias ll='ls -l'
 
alias la='ll -A'
 
alias lx='ll -BX'                  # sort by extension
 
alias lz='ll -rS'                  # sort by size
 
alias lt='ll -rt'                  # sort by date
 
alias lm='la | more'
 
 
# safety features
 
alias cp='cp -i'
 
alias mv='mv -i'
 
alias rm='rm -I'                    # 'rm -i' prompts for every file
 
alias ln='ln -i'
 
alias chown='chown --preserve-root'
 
alias chmod='chmod --preserve-root'
 
alias chgrp='chgrp --preserve-root'
 
</nowiki>}}
 
  
 
==extract==
 
==extract==

Revision as of 23:49, 11 October 2011

Summary help replacing me
Tips and tricks related to so-called "core" utilities on a GNU/Linux system.
Related
Commandline Tools
General Recommendations
GNU Project

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 Template:Package Official package. What follows are various tips and tricks and other helpful information related to these utilities. If sections grow too detailed, please split into separate articles.

extract

The following function will extract a wide range of compressed file types. Add the function to Template:Filename and use it with the syntax Template:Codeline

Template:File

Note: Bash users should make sure extglob is enabled: Template:Codeline. It is enabled by default if using Bash completion. Zsh users should do: Template:Codeline instead.

Another way to do this is to install unp package.

grep

grep is a command line text search utility originally written for Unix. The Template:Codeline command searches files or standard input globally for lines matching a given regular expression, and prints them to the program's standard output.

Beyond aesthetics, Template:Codeline's color output is immensely useful for learning Template:Codeline and Template:Codeline's functionality.

To add it, write the following entry to Template:Filename:

export GREP_COLOR="1;33"
alias grep='grep --color=auto'

The variable Template:Codeline is used to specify the output color, in this example a light yellow color.

Although Template:Codeline's man page states that Template:Codeline is deprecated and that Template:Codeline is preferable, this variable does not work as of Template:Package Official version 2.5.4, so use Template:Codeline for now.

less

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 Template:Codeline and Template:Codeline, Template:Codeline offers a more advanced interface and complete feature-set.[1]

Enable code syntax coloring by adding this line to .bashrc:

export LESS="-R"

Frequent users of the command line interface might want to install Template:Package Official:

# pacman -S lesspipe

Users may now list the compressed files inside of an archive using their pager:

Template:Command

Template:Codeline also grants Template:Codeline 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 Template:Package Official).

Re-login after installing Template:Codeline in order to activate it, or source Template:Filename.

ls

ls is a command to list files in Unix and Unix-like operating systems.

Colored output can be enabled with a simple alias. File Template:Filename should already have the following entry copied from Template:Filename:

alias ls='ls --color=auto'

The next step will further enhance the colored Template:Codeline output; for example, broken (orphan) symlinks will start showing in a red hue. Add the following to Template:Filename and relogin, or source the file:

eval $(dircolors -b)