Difference between revisions of "Using awk grep sed"
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Things that you can accomplish using RegEx within the Vi editor on text files can also be accomplished at the command line with sed. | Things that you can accomplish using RegEx within the Vi editor on text files can also be accomplished at the command line with sed. | ||
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The most basic form is to use sed as a simple search and replace. | The most basic form is to use sed as a simple search and replace. | ||
sed 's/windows/linux/' | sed 's/windows/linux/' | ||
| − | === process text file by removing blanks, unwanted lines, and duplicates === | + | === example: process text file by removing blanks, unwanted lines, and duplicates === |
Get rid of all lines of text containing numerical stats | Get rid of all lines of text containing numerical stats | ||
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== grep == | == grep == | ||
| − | === | + | === example: rgrep === |
rgrep is grep -r or recursive grep | rgrep is grep -r or recursive grep | ||
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Here is an example that searches for multiple specific types | Here is an example that searches for multiple specific types | ||
rgrep -i --include \*.h --include \*.cpp CP_Image ~/path[12345] | rgrep -i --include \*.h --include \*.cpp CP_Image ~/path[12345] | ||
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| + | == awk == | ||
| + | The awk utility is useful for changing data files and generating reports. | ||
| + | |||
| + | By default Awk behaves like 'cat' in that it prints every line of data from the specified file. | ||
| + | awk '{print}' inventory.txt | ||
Revision as of 18:38, 25 February 2020
grep does not alter a file, it only finds matches while awk and sed are text processors.
awk is mostly used for data extraction and reporting. sed is a stream editor. Each one of them has its own functionality and specialties.
Contents
sed
Things that you can accomplish using RegEx within the Vi editor on text files can also be accomplished at the command line with sed.
The most basic form is to use sed as a simple search and replace.
sed 's/windows/linux/'
example: process text file by removing blanks, unwanted lines, and duplicates
Get rid of all lines of text containing numerical stats
sed -i '/[0-9]/d' Razor-Fen.txt
Get rid of all empty lines containing no characters
sed -i '/^\s*$/d' Razor-Fen.txt
Get rid of all duplicate lines
sed -i '$!N; /^\(.*\)\n\1$/!P; D' Razor-Fen.txt
grep
example: rgrep
rgrep is grep -r or recursive grep
If you want to search all text files within all subfolders for a particular matching string, the syntax might not be what you would think
For example, rgrep string *.txt will not search though all text files under the current directory, the correct syntax would be:
rgrep -s string --include \*.txt
Here is an example that searches for multiple specific types
rgrep -i --include \*.h --include \*.cpp CP_Image ~/path[12345]
awk
The awk utility is useful for changing data files and generating reports.
By default Awk behaves like 'cat' in that it prints every line of data from the specified file.
awk '{print}' inventory.txt
