move only if file exists in a shell script

Question

I want to use mv to rename a file:

mv src.txt dest.txt

If the file doesn't exist, I get an error:

mv: cannot stat ‘src.txt’: No such file or directory

How do I use mv only if the file already exists?

I don't want to redirect stderr to dev/null as I'd like to keep any other errors that occur

score 106 · Answer 1 · answered Apr 23 '18 at 01:19

106

One-liner:

[ -f old ] && mv old nu

answered Apr 23 '18 at 01:19

mahemoff

Note that you have to remember to keep the spaces by the brackets. "[-f old]" not working was a surprise for me, who is more used to whitespace-insensitive languages – jakebeal May 20 '22 at 20:23
1

@jakebeal True. The `[` here is actually shorthand for `test`, so the rest (before &) are plain old space-separated arguments like you’d pass to any shell command. – mahemoff May 22 '22 at 07:16

score 79 · Answer 2 · answered Oct 03 '19 at 05:28

79

This one liner returns successfully even if the file is not found:

[ ! -f src ] || mv src dest

answered Oct 03 '19 at 05:28

Mateen Ulhaq

7

(@mahemoff's version returns false if the file is not found.) – Mateen Ulhaq Oct 03 '19 at 05:30
8

```[ ! -d src ] || mv src dest``` if it's a folder – Spidy May 01 '22 at 23:52
I was getting failure notifications in a VS Code tasks running @mahemoff's version. Now I know why. Thanks for the fix. – Chris Redford Jan 27 '23 at 03:13

score 65 · Accepted Answer · answered Oct 29 '15 at 12:52

65

You should test if the file exists

if [ -f blah ]; then
   mv blah destination
fi

answered Oct 29 '15 at 12:52

oz123

3

@Oz123 to be pedantic need to use `[ -r blah ]`, for additional check in read permision – SergA Oct 29 '15 at 14:22
Only -r worked for me even though the problem was that the file wasn't there at all. – Zargold Apr 06 '18 at 17:38
2

@SergA, in that particuliar case, wouldn't ````[ -w blah ]```` be more appropriate since ````mv```` needs write permissions over the file? – ghilesZ Apr 14 '18 at 10:51
3

@ghilesZ, actually there is no need to check write and read file permissions. To move file *you need to have permission to detach it from the directory where it was before, and to attach it to the directory where you're putting it*. Got from [here](https://unix.stackexchange.com/a/149798/170894). – SergA Apr 15 '18 at 13:45
2

For directories use `[ -d myDir ]`. – Joshua Pinter Mar 07 '21 at 19:26

3 Answers3