tee command tutorial in linux/unix with examples and use cases

linux tee command – read from standard input and write to standard output and files.

Copy standard input to each FILE, and also to standard output.

Syntax

tee [OPTION]... [FILE]...

Options

• -a, –append
  append to the given FILEs, do not overwrite
• -i, –ignore-interrupts
  ignore interrupt signals
• -p
  diagnose errors writing to non pipes
• –output-error[=MODE]
  set behavior on write error.

MODE determines behavior with write errors on the outputs:

• warn
  diagnose errors writing to any output
• warn-nopipe
  diagnose errors writing to any output not a pipe
• exit
  exit on error writing to any output
• exit-nopipe
  exit on error writing to any output not a pipe

Examples & Use Cases

Output to standard output and save to file

When we execute linux commands, sometimes we need to save the output to a file and print the output to standard output.

This is the tee command we can use.

➜  ping www.linuxcommands.site | tee ping.log

Output to standard output and append to file

Append output to existing file using tee command “-a” option

➜  ping www.google.com | tee -a ping.log

Output to standard output and output to multiple files

➜ ping www.google.com | tee ping.log g.log

Print stderr and stdout and save to file

Redirect stderr to stdout and use the tee command through the pipeline to save the file and print the information

➜  ./scrip.sh 2>&1 | tee output.log