Substitute first match per line

More sed commands

• Substitute all matches (global)
  sed 's/foo/bar/g' file.txtcopy

  Replace every occurrence per line with the /g flag

• In-place edit
  sed -i 's/old/new/g' config.cfgcopy

  Modify file in-place (no backup); on macOS add empty string: -i ''

• In-place edit with backup
  sed -i.bak 's/old/new/g' file.txtcopy

  Edit in-place and save original as file.txt.bak

• Delete matching lines
  sed '/^#/d' config.txtcopy

  Delete all comment lines starting with #

• Delete blank lines
  sed '/^[[:space:]]*$/d' file.txtcopy

  Remove all empty or whitespace-only lines

all 15 sed commands →