How To Empty A Large File In Linux Witout Deleting Shell Command Delete

Linux General Good Housekeeping

Often when i login into my shell, i get this message:



then to find out how big the size of the file is i send this command:



ok, one meg is not that bad, but lets say i wanted to empty the file, not delete it, so to do that, the process of reducing an existing file to a file with the same name that is 0 bytes large is called "truncating."

For creating a new empty file, the same effect is obtained with the touch command. On an existing file, touch will only update the timestamp. See the Info pages on touch for more details.

so to empty my root mail file, i would send this command:


To "almost" empty a file, use the tail command. Suppose my error.log file becomes rather long because im gettin alot of errors on my web pages. now to remove all but the last 5 lines i can send this command:

first i want to see how large my file is, from this command you can see its 338384078 bytes



Now remove all the lines except the last 5



now i resend the list command and now my error.log file is only 439 bytes