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Babak K. Shandiz
Babak K. Shandiz

Posted on • Originally published at babakks.github.io on

Living in the Shell #2; grep (Pattern Matching) (Part 1)

#productivity #linux #devops #bash

grep🎖️

Prints/filters lines that match a Regular Expression (RE) pattern.

Filter constant 

echo -n 'Hello World!\nI''m Going!\nGoodbye!' | grep "Good"
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 Goodbye!

Filter file content 

cat ~/.bashrc | grep "alias"
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grep "alias" ~/.bashrc
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Filter pattern, with PERL flavour -P 

cat ~/.bashrc | grep -P "^#"
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Prints lines beginning with #.

Filter case-insensitive -i 

echo -n 'Hello World!\nI''m Going!\nGoodbye!' | grep -i "go"
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 I'm Going! Goodbye!

Exclude -v 

echo -n 'Hello World!\nI''m Going!\nGoodbye!' | grep -i -v "go"
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 Hello World!

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