Find and Replace Text within a File Using sed

sed -i 's/original/new/g' file.txt

Explanation

• sed = Stream EDitor
• -i = in-place (i.e. save back to the original file)
• The command string
  • s = the substitute command
  • original = a regular expression describing the word to replace (or just the word itself)
  • new = the text to replace it with
  • g = global (i.e. replace all and not just the first occurrence)
  • file.txt = the file name