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I need to clear a log file with:

cat /dev/null > error.log 

The problem is that the file is owned by root

-rw-r--r-- 1 root root 15505 Feb  9 15:08 error.log

and this doesn't work

$ sudo cat /dev/null > error.log 
-bash: error.log: Permission denied

no idea why... so how could I get around this?

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Just wanted to share a shortcut.. > error.log will zero the file just the same. (Use the answer below to combine it with sudo.) – Aaron Copley Feb 9 '14 at 15:29
man truncate – Zoredache Feb 10 '14 at 8:04
up vote 4 down vote accepted

Try this:

$ sudo sh -c "cat /dev/null > error.log"

The problem is that with the command you used, you are really running two commands: the first cat is run as root (via sudo) but everything else is run as your user. The above method resolves that.

This answer over on U&L has more information on this.

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