Tools a Unix administrator cannot live without [closed]

GNU screen - essential when you're managing large numbers of systems and don't want to have a dozen terminal windows open.

Some I know that I cannot live without...

• tee - allows simultaneous writing to STDOUT (standard output) and a file. Great for viewing information and logging it for later.

• top - the task manager of UNIX, gives a great overview of the system.

• tail -f - allows you to view appended data as a file grows, great for monitoring log files on a server.

• grep - Global Regular Expression Print, great for searching the system for data in files.

• df - reports disk usage of current filesystems.

• du - reports disk usage of a certain file/directory.

• less - needed to view man pages! also useful for viewing output of commands in an easily seekable manner.

• vim/Emacs/nano/pico/ed - whatever your text editor of choice may be, self explanatory of why it's needed.