How to empty ("truncate") a file on linux that already exists and is protected in someway?
LinuxFileCommand LineLinux Problem Overview
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?
Linux Solutions
Solution 1 - Linux
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 - Linux
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
Solution 3 - Linux
This will be enough to set the file size to 0:
> error.log
Solution 4 - Linux
the credit goes for my senior colleague for this:
:> filename
This will not break log files, so you can even use it on syslog, for example.
Solution 5 - Linux
> false|tee fileToTruncate
may work as well
Solution 6 - Linux
Since sudo will not work with redirection >, I like the tee command for this purpose
echo "" | sudo tee fileName
Solution 7 - Linux
I do like this:
cp /dev/null file
Solution 8 - Linux
Any one can try this command to truncate any file in linux system
This will surely work in any format :
truncate -s 0 file.txt
Solution 9 - Linux
You can try also:
echo -n > /my/file