Delete blank lines

More sed commands

• Print specific line numbers
  sed -n '10,20p' file.txtcopy

  Print lines 10 through 20 only (suppress default output with -n)

• Print lines matching pattern
  sed -n '/ERROR/p' app.logcopy

  Print only lines that match ERROR

• Insert line before match
  sed '/^server_name/i # Added by deploy script' nginx.confcopy

  Insert a comment line before every server_name directive

• Append line after match
  sed '/^\[defaults\]/a ansible_python_interpreter=/usr/bin/python3' ansible.cfgcopy

  Append a setting line after the [defaults] header

• Case-insensitive substitution
  sed 's/error/ERROR/gI' file.txtcopy

  GNU sed /I flag for case-insensitive match

all 15 sed commands →