determine whether 'find' cmd found the file or not

mufy · 03-15-2005, 01:22 AM

I am writing a short shell script wherein I would like to continuously search for the presence of a particular file in a particular folder.

This is what I'd like to know; how do I determine the status of the 'find' command so that I can execute a loop till that file has been found? -- Mufy

overlord73 · 03-15-2005, 02:42 AM

to determine the exit status of a command us the $? variable:

QUOTE]# find / ......
# echo $?[/QUOTE]

If return value is zero (0), command is successful.
If return value is nonzero, command is not successful .[

Darin · 03-15-2005, 02:52 AM

This doesn't use the find command, but:

Code:

#!/bin/bash

if [ ! -r /path_to/file ]; then
# if this file can't be read then do something here like
sleep 5
fi

For commands, you can run them as a conditional argument and they will come out TRUE if they don't produce any errors:

Code:

#!/bin/bash

if find /path_to/some.file; then
echo I found the file
fi

if ! find /path_to/some.file; then
echo I didn't find the file
fi

Edit: jinx overlord73

theYinYeti · 03-15-2005, 07:30 AM

As far as I know, find does not give an error status if no files are found. Depending on exactly what you want to do, I'm sure there's a better solutio, though.

Yves.

Darin · 03-15-2005, 07:54 AM

Quote:

Originally posted by theYinYeti
As far as I know, find does not give an error status if no files are found. Depending on exactly what you want to do, I'm sure there's a better solutio, though.

Yves.

AFAIK every command returns, or at least should, an error code on exit that can be used as a comparison operator (or as overlord73 stated, shown with $?). I tested those mini-scripts I posted above and they showed different results before and after touching the appropriate test file. I like the if [! -r file] (not readable) though, since I got that from a Slackware startup script

enemorales · 03-15-2005, 10:14 AM

I'm not sure that looking to the error status would be a good strategy. What would it happen if find cannot access a directory? (for instance, if the user running the program has not permissions) It could happen that the file is found, but an error occuried.

I don't know exactly what "find" returns. Just wanted to point out that you should be careful.

overlord73 · 03-16-2005, 06:18 AM

if "find" cannot access a dir it returns "1".
try as user:

Code:

find /root/ -name filename

Code:

echo $?

jmercier · 03-16-2005, 07:24 AM

You can always just test to see if it returns anything.

Code:

find <dir> -name <filename> | wc -l

Justin