“~/Desktop/test.txt: No such file or directory”

问题:

I\'ve written this script:

#!/bin/bash

file=\"~/Desktop/test.txt\"
echo \"TESTING\" > $file

The script doesn\'t work; it gives me this error:

./tester.sh: line 4: ~/Desktop/test.txt: No such file or directory

What am I doing wrong?

回答1:

Try replacing ~ with $HOME. Tilde expansion only happens when the tilde is unquoted. See info \"(bash) Tilde Expansion\".

You could also do file=~/Desktop without quoting it, but if you ever replace part of this with something with a field separator in it, then it will break. Quoting the values of variables is probably a good thing to get into the habit of anyway. Quoting variable file=~/\"Desktop\" will also work but I think that is rather ugly.

Another reason to prefer $HOME, when possible: tilde expansion only happens at the beginnings of words. So command --option=~/foo will only work if command does tilde expansion itself, which will vary by command, while command --option=\"$HOME/foo\" will always work.

回答2:

FYI, you can also use eval:

eval \"echo \"TESTING\" > $file\"

The eval takes the command as an argument and it causes the shell to do the Tilde expansion.