Pipelines

• A pipe redirects standard output of one command to the standard input of the next one

• Explain these pipelines

  • tac /var/log/messages | less (or “more”)
  • who | grep jeremy
  • cat /var/log/messages | tail

• Can include multiple commands, various input/output redirections, etc.

  • uniq < file.txt | sort | uniq
  • sort -n -k 3 -t : < /etc/passwd | cut -f 1 -d : | xargs echo

• “Filters” are commands that take stdin, do something with it, and output the data on stdout.

• Can span multiple lines for readability

Notes: