Linux empty a file

Quick solution:

cp /dev/null my_filename.txt

Practical example.

In below example we empty the tomcat logs.

Steps:

• Before the file size is 636M
• We executed the command to empty the file cp /dev/null catalina.out
• After the file size is 0

Below we have an example from linux command line.

Before - file size 636M:

root@local:/opt/tomcat/logs# ls -alh
-rw-r-----  1 root root 636M Jan 14 20:22 catalina.out

Execute command:

root@local:/opt/tomcat/logs# cp /dev/null catalina.out

After - file size 0:

root@local:/opt/tomcat/logs# ls -alh
-rw-r-----  1 root root   0 Jan 14 20:23 catalina.out

Other solutions

1. It is posible to redirect empty string into file.

echo -n > my_filename.txt

2. dev-null redirection gives same result

cat /dev/null > my_filename.txt