alias and unalias

alias

In Linux, an alias is a shortcut that references a command. An alias replaces a string that invokes a command in the Linux shell with another user-defined string. Aliases are mostly used to replace long commands, improving efficiency and avoiding potential spelling errors.

Syntax: alias [alias_name] "[name]"

alias: Invokes the alias command.
[alias_name]: Defines the new shortcut that references a command.
[name]: Specifies the command the alias references.

Example: alias la "ls -la"

Here the alias command to create a temporary alias that lasts until the end of the current terminal session. For instance, creating la as an alias for ls -la.

The below figure shows the output of alias la "ls -la".

                              Figure.1. Output of alias command

The below GIF shows the whole process from sourcing scripting file to till the output.

                                    GIF.1. alias output GIF  

Link to GitHub lab: https://github.com/muneeb-mbytes/linux_course/blob/b7_team_kachori/alias_command/alias_command.csh

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unalias

To remove an alias, use the unalias command as shown below,

Syntax: unalias [alias_name]

Example: unalias la

unalias: Invoke unalias command
[alias_name]: shortcut given while doing alias

Here unalias command removes the created alias.

The below figure displays the Output of unalias command, where the created alias la "ls -la" will be removed. The removal of alias can be verified by using which la command and it will display command not found.

                                   Figure.2. Output of unalias command

The below GIF shows the whole process of sourcing the scripting file till the output, here initially alias is created for ls -la as la and the creation of alias is checked by giving which la and to remove alias, the command - unalias la, is used. Then to verify the removal of alias, again we can use which la.

                                          GIF.2. unalias gif output

Link to GitHub lab: https://github.com/muneeb-mbytes/linux_course/blob/b7_team_kachori/alias_command/unalias_command.csh

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To learn environment variables: https://github.com/muneeb-mbytes/linux_course/wiki/19.-Environmental-variables