Find and replace text within a file using commands

Question

How can I replace specific words in a text file using command line?

Answer 1

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

Answer 2

There are a number of different ways to do this. One is using sed and Regex. SED is a Stream Editor for filtering and transforming text. One example is as follows:

marco@imacs-suck: ~$ echo "The slow brown unicorn jumped over the hyper sleeping dog" > orly
marco@imacs-suck: ~$ sed s/slow/quick/ < orly > yarly
marco@imacs-suck: ~$ cat yarly
The quick brown unicorn jumped over the hyper sleeping dog

Another way which may make more sense than < strin and > strout is with pipes!

marco@imacs-suck: ~$ cat yarly | sed s/unicorn/fox/ | sed s/hyper/lazy/ > nowai
marco@imacs-suck: ~$ cat nowai 
The quick brown fox jumped over the lazy sleeping dog