Search and replace in bash using regular expressions

by

Use sed:

MYVAR=ho02123ware38384you443d34o3434ingtod38384day
echo "$MYVAR" | sed -e 's/[a-zA-Z]/X/g' -e 's/[0-9]/N/g'
# prints XXNNNNNXXXXNNNNNXXXNNNXNNXNNNNXXXXXXNNNNNXXX

Note that the subsequent -e‘s are processed in order. Also, the g flag for the expression will match all occurrences in the input.

You can also pick your favorite tool using this method, i.e. perl, awk, e.g.:

echo "$MYVAR" | perl -pe 's/[a-zA-Z]/X/g and s/[0-9]/N/g'

This may allow you to do more creative matches… For example, in the snip above, the numeric replacement would not be used unless there was a match on the first expression (due to lazy and evaluation). And of course, you have the full language support of Perl to do your bidding…

More Related Contents:

  1. Awk – replace coumn 2 in table 1 from coumn 2 in table 2 based on matching data in column 1 (common between tables)
  2. bash regex with quotes?
  3. Find and kill a process in one line using bash and regex
  4. RE error: illegal byte sequence on Mac OS X
  5. Bash Regular Expression — Can’t seem to match any of \s \S \d \D \w \W etc
  6. How do I use regular expressions in bash scripts?
  7. Using the star sign in grep
  8. How to match digits in regex in bash script
  9. Regular expressions in a Bash case statement
  10. Regex matching in a Bash if statement
  11. Extract substring using regexp in plain bash
  12. Bash, grep between two lines with specified string
  13. Fully qualified domain name validation
  14. Why is sed not recognizing \t as a tab?
  15. What does ‘\K’ mean in this regex?
  16. Insert linefeed in sed (Mac OS X)
  17. Does bash support word boundary regular expressions?
  18. Remove duplicates from text file based on second text file
  19. How to match a pattern given in a variable in awk?
  20. Replace a word with multiple lines using sed?
  21. replace a unknown string between two known strings with sed
  22. Recursively change file extensions in Bash
  23. How can I match a string with a regex in Bash?
  24. Rename files using a regex with bash [duplicate]
  25. How can I match spaces with a regexp in Bash?
  26. How to change date format in sed?
  27. How to execute a Bash command only if a Docker container with a given name does not exist?
  28. Grep and regex – why am I escaping curly braces?
  29. Bash – Regex for HTML contents
  30. How to extract domain name from url?

Leave a Comment