Eikonal Blog

2010.07.13

Command line based text replace

sed

  • sed 's/Mark Monre/Marc Monroe/' 1.txt > 2.txt
  • find ./* -type f -exec sed -i 's///g' {} \;

The “replace” command

  • Syntax:
    replace OLD-STRING NEW-STRING OUTPUT-FILE
  • Example:
    $ replace UNIX Linux  newfile
  • Example:
    $ cat /etc/passwd | replace : '|'
  • Partial support for regular expressions: \^ – matches start of line, and $ matches end of line.
  • Example: replace all IP address 192.168.1.2 start of line:
    $ replace \^192.168.1.2 192.168.5.10  newfile
  • a bash script, ‘fixer.sh’
    #!/bin/bash
    replace CHANGEFROM CHANGETO $1.tmp
    rm $1
    mv $1.tmp $1
    

    now run this command line:

    $ grep CHANGEFROM |cut -d':' -f1 |xargs -n 1 fixer.sh

    the results is that all files in the directory (or whatever you grep for) will be changed automagically.
    just make sure the grep doesn’t include the fixer script itself, or it will die half-way through changing when execute permissions are reset!


Perl


Sources:


Related: Regular expressions – https://eikonal.wordpress.com/2010/04/02/regular-expressions/ | Perl online – https://eikonal.wordpress.com/2010/02/15/perl-online/

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