别名不在Shell脚本中执行

Question

In my bashrc file I have n number of alias. But, If I execute via shell script, it will not give expected output. Why it will be like this. Is there any way to solve this problem.

Thanks in advance.

Answer 1

Aliases (as set using alias name=value ) are only used in an interactive context, ie when the user types something on the command line. They are never executed by a script (unless a non-interactive shell is explicitly tweaked to do this using the shopt -s expand_aliases ):

#!/bin/bash
alias ttt=date
ttt  # will fail!

Sourcing a configuration script which defines aliases will not change anything about this. Scripts simply will not execute aliases.

To achieve what you want, rewrite your aliases as shell functions:

#!/bin/bash
ttt() {
  date
}
ttt  # will succeed!

Shell functions can replace aliases completely but there are some more things to know and consider:

1. You can even export shell functions so that child shells also have them. Use export -f ttt for this.
2. Shell functions can override other commands so they can interfere in the behaviour of scripts (unlike aliases which are never executed in scripts). Keep this in mind in case you plan to override things like cd or ls .
3. An overridden built-in of the shell (eg cd ) can still be reached by calling it as builtin cd /my/direc/tory .
4. Argument handling is quite different from aliases (and much more powerful).