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regexbashfilepath

Regular expression for file path which doesn't allow parent directories

I'm looking to write a regex for a file path that must start with some prefix. In this case it should start with '/tank/home/'. I also want to make sure that it contains no '/..' -- no jumping up to parent directories.

I spent a while fiddling around without coming up with anything quite right. I settled on using two regexes, the first which must match and the second which must not match:

'^/tank/home/'

'/\.\.(/.*)?$'

Does this do what I think it does? Is there an easier way?

This is in a bash script, for what it's worth.

Solution

  • You can expand Dav's regex to include an extra trailing slash:

    ^(?!.*/\.\./.*)/tank/home.*$

    But... a better option might be to make sure that the result of the path is something that starts under /tank/home:

    FILEPATH=$(readlink -f $YOURFILE)
[[ $FILEPATH =~ ^/tank/home/ ]] && echo "starts with /tank/home/"