Difference between revisions of "Perl-regex"
From Bashlinux
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| − | This command line replaces all the instances of ''old string'' with ''new string'' that are found in `/path/to/the/file`. To replace only the first instance, remove the ''g ''at the end of the command. |
+ | This command line replaces all the instances of ''old string'' with ''new string'' that are found in `/path/to/the/file`. To replace only the first instance, remove the ''g ''at the end of the command. |
* '''Conditional match''' |
* '''Conditional match''' |
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| − | This command line search only for the lines that matches ''my unique string'' and then replaces ''old string'' with ''new string'' |
+ | This command line search only for the lines that matches ''my unique string'' and then replaces ''old string'' with ''new string'' |
* '''Search and replace using bash shell variables''' |
* '''Search and replace using bash shell variables''' |
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| − | In order to get this done is convenient to use `sed` instead `perl` command. |
+ | In order to get this done is convenient to use `sed` instead `perl` command. |
== Remove/replace a whole line == |
== Remove/replace a whole line == |
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| − | This command line removes all the lines that matches ''my unique string'' |
+ | This command line removes all the lines that matches ''my unique string'' |
Revision as of 09:21, 3 February 2010
Perl Regex
Search and replace a word or phrase
- All matches
perl -pi -e 's/old string/new string/g' /path/to/the/file
This command line replaces all the instances of old string with new string that are found in `/path/to/the/file`. To replace only the first instance, remove the g at the end of the command.
- Conditional match
perl -pi -e 's/old string/new string/ if m/my unique string/' /path/to/the/file
This command line search only for the lines that matches my unique string and then replaces old string with new string
- Search and replace using bash shell variables
sed -ie s%old string%$BASH_VARIABLE% /path/to/the/file
In order to get this done is convenient to use `sed` instead `perl` command.
Remove/replace a whole line
- Conditional match
perl -pi -e '$_="" if m/my unique string/' /path/to/the/file
This command line removes all the lines that matches my unique string
