Useful Commands

• Grep -- learn regular expressions! Careful with options

• Awk

  • Scripting/programming language in its own right. I mostly use it to parse fields delimited by whitespace like so:
  • ps auxw|grep bash | awk '{print $2}'
  • Say no to advanced awk scripts -- choose Perl (or Python)

• Cut

  • Useful for parsing files with a given delimeter
  • grep -v /home /etc/passwd | cut -d : -f 1

• Sed

  • Stream editor, make changes based on regular expressions
  • Strip comments from input files:
    • /bin/sed -e 's/\#.*$//g'

Notes: