Why can’t I remove a file inside a while-read loop with a Bash script?

Question

I have a polling script that will occasionally pop out the name of a file to delete. The file to delete will always be located on an NFS-mounted filesystem.

So I wrote this Bash script:

#!/bin/bash
 
/usr/local/bin/polling.sh |
while read FILE_TO_DELETE;
do
   rm "${FILE_TO_DELETE}"
done

When this script is run, I get:

"cannot remove '/file/that/needs/deleting.txt': Device or resource busy".

If I run the rm command outside the while-read loop, it works just fine, so it's not a permission or open file issue.

Can anyone explain why the rm command doesn't work inside this loop but works fine outside of it?

FWIW, I looked at the file context before and after modifying the file, using ls -laZ, and they look the same. This is truly perplexing.

As suggested by the Stack Overflow answer Automatically solve rm cannot remove path : device or resource busy error try running lsof +D /file/that/needs/deleting to see if that identifies what has the file open. — Chester Gillon
– Chester Gillon, Commented 15 hours ago
I had also tried adding lsof /file/that/needs/deleting to the script. It shows that nothing is holding the file open. — Richard Lawson
– Richard Lawson, Commented 15 hours ago
NFS-mounted remote file system. I also want to emphasize that the rm command will work if it is run outside of the while-read loop, so it's not a permissions issue. I can also delete the file just fine from the command line. — Richard Lawson
– Richard Lawson, Commented 15 hours ago
Do the problematic filenames start with .nfs? See the Unix & Linux NFS mount: Device or resource busy. — Chester Gillon
– Chester Gillon, Commented 15 hours ago

Richard Lawson · Accepted Answer · 2025-12-31 19:05:27Z

5

I found that if I modified the file (by, say, appending an empty line to the end of the file), I could then run the rm command from inside the loop. I don't know why that is; somehow saving it locally overwrites some remote file attribute that prevented deletion within my loop.

That led me to try using the shred command, which overwrites the file before deleting it. That worked a charm. So I'm leaving this solution up in case it helps someone else, even if I don't fully understand why it's necessary.

#!/bin/bash
 
/usr/local/bin/polling.sh |
while read FILE_TO_DELETE;
do
   shred -n 1 -u "${FILE_TO_DELETE}"
done

answered 13 hours ago

Richard Lawson

815 bronze badges

New contributor

This has got to be some kind of crazy NFS-specific thing...

Glenn Willen
– Glenn Willen

2026-01-01 01:32:07 +00:00
Commented 7 hours ago

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Giacomo1968 · Accepted Answer · 2025-12-31 22:12:01Z

1

I don’t know why this is happening, but it could be related to file ownership and/or permissions.

So try to force the delete with the -f parameter like this:

rm -f "${FILE_TO_DELETE}"

If that doesn’t work, try changing the rm to ls -la to see if you can glean any insight on what might be happening:

ls -la "${FILE_TO_DELETE}"

Or even use the Z parameter to check for SELinux context with:

ls -laZ "${FILE_TO_DELETE}"

edited 10 hours ago

answered 15 hours ago

Giacomo1968

59.1k23 gold badges180 silver badges225 bronze badges

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