Over a million developers have joined DZone.
{{announcement.body}}
{{announcement.title}}

Grep Quotes in Linux

DZone's Guide to

Grep Quotes in Linux

Grep is your friend, and a powerful tool. This article looks at some common scenarios for grep and how it is used to address them.

· DevOps Zone ·
Free Resource

Is the concept of adopting a continuous everything model a daunting task for your fast moving business? Read this whitepaper to break down and understand one of the key pillars of this model in Continuous Governance: The Guardrails for Continuous Everything.

Count line when words have been matched:

$ grep -c 'word' /path/to/file

Pass the -n option to precede each line of output with the number of the line in the text file:

$ grep -n 'root' /etc/passwd

Ignore word case:

$ grep -i 'word' /path/to/file

Use grep recursively under each directory:

$ grep -r 'word' /path/to/file

Use grep to search 2 different words:

$ egrep -w 'word1|word2' /path/to/file

Grep invert match:

$ grep -v 'word' /path/to/file

You can force grep to display output in colors, enter:

$ grep --color 'word' /path/to/file

You can limit the results count:

$ grep -m 10 'word' /path/to/file

You can match regular expression in files (Syntax: grep "REGEX" filename):

$ grep 'word1.*word2' /path/to/file
  • ? The preceding item is optional and matched at most once.
  • * The preceding item will be matched zero or more times.
  • + The preceding item will be matched one or more times.
  • {n} The preceding item is matched exactly n times.
  • {n,} The preceding item is matched n or more times.
  • {,m} The preceding item is matched at most m times.
  • {n,m} The preceding item is matched at least n times, but not more than m times.

Display N lines Around Match

Grep can display N lines after match (Syntax: grep -A <N> "string" filename):

$ grep -A 2 'word' /path/to/file

The following example prints the matched line, along with the two lines after it.

$ grep -A 2 -i 'word' /path/to/file

-C is the option which prints the specified N lines before the match.

$ grep -C 2 'word' /path/to/file

Are you looking for greater insight into your software development value stream? Check out this whitepaper: DevOps Performance: The Importance of Measuring Throughput and Stability to see how CloudBees DevOptics can give you the visibility to improve your continuous delivery process.

Topics:
grep ,linux ,search ,script ,command line

Published at DZone with permission of

Opinions expressed by DZone contributors are their own.

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}