Re: [Help-bash] No tilde expansion in [[..]] when reading input with read

[Chris Down]

Hi,

On 2013-02-25 00:03, Suvayu Ali wrote:
> I'm trying to read in a directory name with read, later when I test it
> with [[ -d $mydir ]] it fails if there is a tilde.  I'm guessing tilde
> expansion is not happening in [[...]].  I have attached a test script
> which demonstrates my issue.

The reason it is not expanding is not because of anything in [[, it's because
it's not interpreted when you're reading it into the variable using `read'.

    $ read x
    ~/
    $ echo "$x"
    ~/

If you need to interpret the tilde, you should manually replace it (do not use
`eval' without thinking long and hard about it first, you can quite easily allow
arbitrary command execution). One way of doing this is to use bash's built-in
parameter expansion:

    $ x=${x/\~/$HOME}
    $ echo $x
    /home/chris/

Obviously this doesn't account for cases like ~chris, for example, but it's a
start.

Best,

Chris