How to empty ("truncate") a file on linux that already exists and is protected in someway?

I have a file called error.log on my server that I need to frequently truncate. I have rw permissions for the file. Opening the file in vi > deleting all content > saving works (obviously). But when I try the below

cat /dev/null > error.log

I get the message

File already exists.

Obviously there is some kind of configuration done on the server to prevent accidental overriding of files. Can anybody tell how do I "truncate" the file in a single command?

Solution 1:

You have the noclobber option set. The error looks like it's from csh, so you would do:

cat /dev/null >! file

If I'm wrong and you are using bash, you should do:

cat /dev/null >| file

in bash, you can also shorten that to:

>| file

Solution 2:

You can also use function truncate

$truncate -s0 yourfile

if permission denied, use sudo

$sudo truncate -s0 yourfile

Help/Manual: man truncate

tested on ubuntu Linux