Bash parameter expansion works only in interactive shell, but not in script

问题

In user's console I have bash:

$ echo $SHELL
/bin/bash
$ bash --version
GNU bash, version 4.2.46(1)-release (x86_64-redhat-linux-gnu)

I have code in file test.sh:

$ cat test.sh
aaa='---aa-aa---'
echo "${aaa}"
echo 'does not work...'
# trim "-"
echo ${aaa/+(-)}
echo ${aaa%%+(-)}
echo 'works for one symbol...'
echo ${aaa%-}
echo ${aaa/-}

The last two rows work fine but previous ones.

$ bash test.sh
---aa-aa---
does not work...
---aa-aa---
---aa-aa---
works for one symbol...
---aa-aa--
--aa-aa---

In the same time, if you would try to make this console it works:

$ aaa='---aa-aa---'
$ echo ${aaa/+(-)}
aa-aa---
$ echo ${aaa%%+(-)}
---aa-aa

So, why it doesn't work in a script?

回答1:

You seem to have shopt -s extglob enabled in your interactive shell, which turns on extended globbing. This is not the default behavior, and needs to be explicitly enabled in your script. See extended pattern matching in the bash hackers wiki for details.

来源：https://stackoverflow.com/questions/40180295/bash-parameter-expansion-works-only-in-interactive-shell-but-not-in-script