Q. Sometime I get confuges whether command is an alias or it is real command. How do I find out if shell command is aliased?

A: You need to use type command. It rells whether command is an alias, function, buitin command or executable command file.

For example:

$ type –all ls

Output:

ls is aliased to `ls --color=auto'
ls is /bin/ls

OR

$ type alias

alias is a shell builtin

So for each command, it indicate how it would be interpreted if used as a command name. You can also try out following options:

• If the -t option is used, `type’ outputs a single word which is one of alias, keyword, function, builtin, file etc
• If the -p flag is used, `type’ either returns the name of the disk file that would be executed, or nothing if `type -t NAME’ would not return `file’.
• If the -a flag is used, `type’ displays all of the places that contain an executable named `file’. This includes aliases, builtins, and functions, if and only if the -p flag is not also used.
• The -f flag suppresses shell function lookup.
• The -P flag forces a PATH search for each NAME, even if it is an alias, builtin, or function, and returns the name of the disk file that that would be executed.

See also:

• How Linux or UNIX Understand which program to run – PART I and II
  

ADVERTISEMENTS