Regex: Remove lines containing "help", etc
RegexNotepad++Regex Problem Overview
I have a long document of commands. Using Notepad++ or regex, I want to delete all lines containing "help" including keyboard_help, etc.
How can this be done?
Regex Solutions
Solution 1 - Regex
This is also possible with Notepad++:
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Go to the search menu, Ctrl + F, and open the Mark tab.
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Check Bookmark line (if there is no Mark tab update to the current version).
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Enter your search term and click Mark All
- All lines containing the search term are bookmarked.
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Now go to the menu Search → Bookmark → Remove Bookmarked lines
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Done.
Solution 2 - Regex
Another way to do this in Notepad++ is all in the Find/Replace dialog and with regex:
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Ctrl + h to bring up the find replace dialog.
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In the
Find what:text box include your regex:.*help.*\r?\n(where the\ris optional in case the file doesn't have Windows line endings). -
Leave the
Replace with:text box empty. -
Make sure the Regular expression radio button in the Search Mode area is selected. Then click
Replace Alland voila! All lines containing your search termhelphave been removed.
Solution 3 - Regex
Easy task with grep:
grep -v help filename
Append > newFileName to redirect output to a new file.
Update
To clarify it, the normal behavior will be printing the lines on screen. To pipe it to a file, the > can be used. Thus, in this command:
grep -v help filename > newFileName
grepcalls thegrepprogram, obviously-vis a flag to inverse the output. By defaulf,grepprints the lines that match the given pattern. With this flag, it will print the lines that don't match the pattern.helpis the pattern to matchfilenameis the name of the input file>redirects the output to the following itemnewFileNamethe new file where output will be saved.
As you may noticed, you will not be deleting things in your file. grep will read it and another file will be saved, modified accordingly.
Solution 4 - Regex
Search with a regular expression:
^.*(help).*$
Solution 5 - Regex
You can do this using sed: sed '/help/ d' < inputFile > outputFile
Solution 6 - Regex
If you're on Windows, try findstr. Third-party tools are not needed:
findstr /V /L "searchstring" inputfile.txt > outputfile.txt
It supports regex's too! Just read the tool's help findstr /?.
P.S. If you want to work with big, huge files (like 400 MB log files) a text editor is not very memory-efficient, so, as someone already pointed out, command-line tools are the way to go. But there's no grep on Windows, so...
I just ran this on a 1 GB log file, and it literally took 3 seconds.