How to manually expand a special variable (ex: ~ tilde) in bash

Question

I have a variable in my bash script whose value is something like this:

~/a/b/c

Note that it is unexpanded tilde. When I do ls -lt on this

Answer 1

Expanding (no pun intended) on birryree's and halloleo's answers: The general approach is to use eval, but it comes with some important caveats, namely spaces and output redirection (>) in the variable. The following seems to work for me:

mypath="$1"

if [ -e "`eval echo ${mypath//>}`" ]; then
    echo "FOUND $mypath"
else
    echo "$mypath NOT FOUND"
fi

Try it with each of the following arguments:

'~'
'~/existing_file'
'~/existing file with spaces'
'~/nonexistant_file'
'~/nonexistant file with spaces'
'~/string containing > redirection'
'~/string containing > redirection > again and >> again'

Explanation

• The ${mypath//>} strips out > characters which could clobber a file during the eval.
• The eval echo ... is what does the actual tilde expansion
• The double-quotes around the -e argument are for support of filenames with spaces.

Perhaps there's a more elegant solution, but this is what I was able to come up with.