glob pattern in bash don't recognize '('

Question

When running the following command: ``` rm -rf !(file1|file2) ``` all files except file1 and file2 are removed; as intended. When either placing this command in a bash script: ``` #!/bin/bash rm -rf !(file1|file2) ``` or running it using bash -c: ``` bash -c "rm -rf !(file1|file2)" ``` I receive the following error: ``` syntax error ner unexpected token '(' ``` I have tried setting the shell options using ``` shopt -s extglob ``` yeilding in: ``` bash -c "shopt -s extglob; rm -rf !(file1|file2)" ``` to enable glob according to: https://superuser.com/questions/231718/remove-all-files-except-for-a-few-from-a-folder-in-unix and some other questions as well. Still it doesn't work, and I'm at loss.

Accepted Answer

First of all, for safety, let's do our testing with `echo !(file1|file2)` instead of `rm -rf !(file1|file2)`.

Anyway, bash does some parsing of the entire command line before executing the `shopt -s extglob` command. When bash encounters the `(`, the `extglob` option isn't set yet. That's why you get the error.

Try this instead:

```
bash -O extglob -c 'echo !(file1|file2)'
```

In your script, you just need to turn on the option as a separate command line before relying on it:

```
#!/bin/bash
shopt -s extglob
echo !(file1|file2)
```

You can actually do this with the `-c` flag also:

```
bash -c 'shopt -s extglob
echo !(file1|file2)'
```

Or even like this:

```
bash -c $'shopt -s extglob
echo !(file1|file2)'
```

glob pattern in bash don't recognize '('

Solution

Problem