I am practicing with parameter substitution in bash.
I wrote the following dummy script:
#!/bin/bash
var1="/some/path/to/file/the_file.arbitrary.n.ext.0.random.ext"
var2="/some/path/to/file/the_file.arbitrary.n.ext.0.ext"
pattern='.[0-9]?(.random).ext'
echo "${pattern}"
echo "${var1/${pattern}/}"
echo "${var2/${pattern}/}"
Basically, the pattern is meant to strip off the last part of the file name.
Executing the dummy script results in:
~$ ./dummy.sh
.[0-9]?(.random).ext
/some/path/to/file/the_file.arbitrary.n.ext.0.random.ext
/some/path/to/file/the_file.arbitrary.n.ext.0.ext
whereas evaling the script's contents or, equivalently, the direct input of that sequence of commands in the interactive shell, results in:
~$ eval "$(cat dummy.sh)"
.[0-9]?(.random).ext
/some/path/to/file/the_file.arbitrary.n.ext
/some/path/to/file/the_file.arbitrary.n.ext
The pattern '.[0-9]*.ext' works, so the issue clearly is confined to the sub-string '?(.random)'. The issue could be with ?, since it is a reserved character in the context of parameter substitution. However, if that were the issue, I would expect the pattern to either fail or succeed the same in both cases.
Where's the probably obvious pitfall?
