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sometimes, grep alone is enough to do the task
April 14th, 2009 mysurface Posted in Text Manipulation, grep | Hits: 92724 |
One thing that makes UNIXes command line so powerful is because of pipelines. Pipelines is a set of processes chained by their standard streams, so that the output of each process (stdout) feeds directly as input (stdin) of the next one. Simple words, pipelines pass the outcomes of a particular command as input to another command, and these chained allows you to do a command line combo!
A complex combo, I have constructed one last time in post what is your 10 common linux commands?
history | awk '{CMD[$2]++;count++;}END { for (a in CMD)print CMD[a] " " CMD[a]/count*100 "% " a;}' | \
grep -v "./" | \
column -c3 -s " " -t | \
sort -nr | nl | head -n10
But sometimes we tend to misuse them, I found someone likes to do this:
cat foobar.txt | grep "barfoo"Actually grep alone is enough to do the search, we do not need cat or meow for that. As I show him this:
grep "barfoo" foobar.txtAnother example is list the names of all files under a given directory that match a particular string. Let say I wanna obtain a list of files that have string “foobar”.
find /opt/src/kmess -type f | xargs grep -l "foobar"Hey! find is cool but grep alone is enough to do the job.
grep -lr "foobar" /opt/src/kmessTry to goes through the grep manual, you will find out that grep is more powerful than what you expect.
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