https://DevOpsCloud.io -- Cloud Monk Losang Jinpa

Return to Pseudonym, Linux Commands, Python glossary, Python lingo, Python

Python alias - alias - “An alternative name for an object. For example, in a = []; b = a the variable b is an alias to the list bound to a.” (FlntPy 2022)

Snippet from Wikipedia: Alias

Alias may refer to:

• Pseudonym, a fictitious name that a person or group assumes for a particular purpose
  • Pen name, a pseudonym adopted by an author and printed on the title page or by-line of their works in place of their real name
  • Stage name, a pseudonym used by performers and entertainers
• Nickname, a substitute for the proper name of a familiar person, place or thing
• Code name, a code word or name used, sometimes clandestinely, to refer to another name, word, project, or person

Creative Commons Attribution-Share Alike 4.0

Snippet from Wikipedia: Alias (command)

In computing, alias is a command in various command-line interpreters (shells), which enables a replacement of a word by another string. It is mainly used for abbreviating a system command, or for adding default arguments to a regularly used command. alias is available in Unix shells, AmigaDOS, 4DOS/4NT, FreeDOS, KolibriOS, Windows PowerShell, ReactOS, and the EFI shell. Aliasing functionality in the MS-DOS and Microsoft Windows operating systems is provided by the DOSKey command-line utility.

An alias will last for the life of the shell session. Regularly used aliases can be set from the shell's rc file (such as .bashrc) so that they will be available upon the start of the corresponding shell session. The alias commands may either be written in the config file directly or sourced from a separate file.

Creative Commons Attribution-Share Alike 4.0

An alias is simply that - another name with which to refer to a command. Aliases allow you to create shorter or more familiar names for commonly used commands. Another benefit lies in being able to not only alias the command, but the first few arguments, as well. Aliases were introduced by csh and later incorporated in bash and others.

The exact syntax used to set an alias depends on your shell. For Bourne-type shells (ksh, bash, etc., though not sh), the syntax is:

$ alias ''name''=''command''

If the command has arguments, then quotes (single or double) must be used:

$ alias ''name''="''command'' ''argument'' ..."

For csh-type shells (csh, tcsh, etc.), quotes aren't needed:

$ alias ''name'' ''command'' [''arguments'' ...]

As you can see, the main differences are the equals sign after the name of the alias and whether quotes are needed. When issued without arguments, alias prints a list of the currently defined aliases.

When issued at the command line an alias only takes effect for that shell. To make it permanant, the alias must be saved in one of the shell configuration files. For bash, they are ordinarily placed in the ~/.bashrc file for per-user configuration, or in /etc/profile for all users. For tcsh, the file ~/.tcshrc is the right place, or /etc/login for all users.

A simple alias for DOS users:

$ alias dir="ls -l"

Here is an example of a complicated alias:

$ alias topcom='sort ~/.bash_history | uniq -ci | sort -r | less'

This alias makes it is easy to look for frequently used commands that might merit being turned into yet more aliases.

Here is an another example to see mounted partitions:

$ alias mnt='mount | grep -i /dev/[h,s]d[a..g] | sort'

Shell functions can accomplish the same effect as aliases, but the latter are simpler. Unlike functions, they do not permit variable substitution.

For instance even something as simple as:

$ bak () { cp -a $1 $1.bak }

cannot be defined as an alias due to the variable “$1”.

To set an alias persistently for all users, all shells (ksh, bash, …) and all type of shells (login shells and non-login shells) you need to

• modify /etc/profile

:for logIn shells

• modify /etc/bash_bashrc

:for non-login bash shells

Use unalias

• Fair Use Source: http://wiki.linuxquestions.org/wiki/Alias

• Shell pages: ksh, bash, csh, tcsh

Linux Command

Fair Use Sources:

• B09WZJMMJP (FlntPy 2022)