10 Examples Of Grep Ascendancy Inwards Unix Too Linux

The grep command is 1 of the most oftentimes used UNIX command stands for "Global Regular Expression Print" along with find, chmod, and tar command inwards UNIX. grep command inwards Unix operating organization e.g. Linux, Solaris, BSD, Ubuntu or IBM AIX is used to search files for matching patterns, yesteryear using grep command inwards Unix you lot tin search a file which contains a detail discussion or detail pattern. UNIX grep command also provides several useful command business choice which tin move used to heighten the functionality of grep command e.g. yesteryear using grep -v you lot tin listing downwards all files which don't incorporate a discussion i.e. excluding files which matches a pattern, grep -c volition impress count of matching blueprint inwards a file etc. One of the pop examples of grep command is to find empty files in addition to directories inwards Unix.

This grep command tutorial is non nearly theory of UNIX grep but practical work of grep command inwards UNIX in addition to hither I am sharing my sense on work of grep command inwards Linux amongst an aim that this would serve every bit quick guide or tutorial for using grep inwards UNIX for novel beginners in addition to help them to empathize the grep command amend in addition to its thoughtful usage inwards UNIX or Linux.

Many people work grep only for finding words inwards a file in addition to missed the existent potential of grep yesteryear non using all its powerful command business options in addition to it's regular expression capability which could non exclusively salve a lot of fourth dimension but also plant every bit a keen in addition to powerful tool spell analyzing large gear upwards of information or log files.

10 ways to work Grep command inwards Unix - examples

Following examples of grep command inwards UNIX are based on my sense in addition to I work them on a daily footing inwards my work. Grep command is also portion of whatever beginners UNIX command tutorial every bit it is an essential command to larn inwards lodge to piece of work efficiently inwards whatever UNIX environs e..g Redhat Linux, Ubuntu, IBM AIX, Oracle Solaris or BSD.

Anyway, these examples are yesteryear no agency consummate thus delight contribute you're ain grep command tips or how you lot are using grep inwards Linux to acquire inwards to a greater extent than useful in addition to allow all of us to practice goodness from each other's sense in addition to piece of work efficiently inwards UNIX or Linux.

Example 1: How to ignore some words spell doing a search using grep inwards UNIX

Finding relevant discussion in addition to exclusion of irrelevant word. Most of the fourth dimension I expect for Exception in addition to Errors inwards log files in addition to sometimes I know sure enough Exception I tin ignore thus I work grep -v choice to exclude those Exceptions

grep Exception logfile.txt | grep -v ERROR

This grep command illustration volition search for discussion "Exception" inwards logfile.txt in addition to impress them but since nosotros direct maintain piped out of start grep command to mo grep command which volition exclude all lines which stand upwards for globe "ERROR". To brand this grep illustration to a greater extent than concrete let's run across some other example, hither nosotros direct maintain a file which contains iii lines every bit shown below:

$ truthful cat example.txt UNIX operating system UNIX and Linux operating system Linux performance system

Now nosotros desire to search all lines inwards file example.txt which contains discussion UNIX but same fourth dimension doesn't incorporate globe Linux.

$ grep UNIX example.txt UNIX operating system UNIX and Linux operating system 

Now to exclude all lines which incorporate Linux nosotros volition apply some other grep command inwards this output amongst choice -v to exclude matching discussion every bit shown inwards below grep command:

$ grep UNIX example.txt | grep -v Linux UNIX operating system

Example 2: How to count the occurrence of a discussion inwards a file using grep command

If you lot desire to count on a detail discussion inwards the log file you lot tin work grep -c choice to count the word. Below an illustration of command volition impress how many times the discussion "Error" has appeared inwards logfile.txt.

$ grep -c "Error" logfile.txt

If nosotros apply this grep command on our illustration file to honor how many lines incorporate discussion e.g. UNIX has occurred inwards the file:

$ grep -c UNIX example.txt 2

Example 3: printing lines before in addition to after of matching discussion using grep

Sometimes nosotros are non only interested inwards matching business but also on lines only about matching lines peculiarly useful to run across what happens before whatever Error or Exception. grep --context choice allows us to impress lines only about matching pattern. Below an illustration of grep command inwards UNIX volition impress 6 lines only about matching business of discussion "successful" inwards logfile.txt

$ grep --context=6 successful logfile.txt

Show an additional vi lines after matching real useful to run across what is only about in addition to to impress the whole message if it splits only about multiple lines. You tin also work command business choice "C" instead of "--context" for example

$ grep -C 2 'hello' *

Prints 2 lines of context only about each matching line.

Example 4: How to search blueprint using egrep in addition to regular expression

stands for extended grep in addition to it is to a greater extent than powerful than grep command inwards Unix in addition to allows to a greater extent than regular exception similar you lot tin work "|" choice to search for either Error or Exception yesteryear executing only 1 command.

$ egrep 'Error|Exception' logfile.txt

Example 5: How to practice case-insensitive searching using grep inwards Linux

If you lot desire to practice instance insensitive search in addition to then work -i choice from grep command inwards UNIX. grep -i command volition honor an occurrence of both Error, error, in addition to ERROR in addition to quite useful to display whatever sort of Error from the log file.

$ grep -i Error logfile

Example 6: How to search patterns inwards gzip files using the zgrep command

zgrep is some other keen version of grep command inwards Unix which is used to perform the same performance every bit grep does but amongst .gz files. Many times nosotros gzip the quondam file to trim the size in addition to afterwards wants to expect or honor something on those files. zgrep is your human being for those days. Below command volition impress all files which direct maintain "Error" on them.

$ zgrep -i Error *.gz

Example 7: How to search the whole discussion inwards a file using grep command

You tin work grep -w command inwards UNIX to honor the whole discussion instead of a only pattern, every bit shown inwards the next the example. This illustration volition exclusively impress lines from logfile.txt which contains total discussion ERROR.

$ grep -w ERROR logfile.txt

Above grep command inwards UNIX searches exclusively for instances of 'ERROR' that are entire words; it does non stand upwards for `SysERROR'.
For to a greater extent than control, work `\<' in addition to `\>' to stand upwards for the start in addition to terminate of words. For example:

$ grep 'ERROR>' *

Searches exclusively for words ending inwards 'ERROR', thus it matches the discussion `SysERROR'.

Example 8: UNIX command to display files names which incorporate given word 

Another useful grep command business choice is "grep -l" which display exclusively the file names which stand upwards for the given pattern. Below command volition exclusively display file names which direct maintain ERROR?

$ grep -l ERROR *.log

grep -l 'main' *.java volition listing the names of all Java files inwards the electrical flow directory whose contents get upwards `main'.

Also, honor command inwards UNIX tin move used inwards house of grep at many places. If you lot desire to leverage the total potential of grep, in addition to then using Grep bag reference is non a bad idea, an ideal grep reference for organization admin, developers, in addition to safety professionals

Example 9: grep command choice to display lines numbers

If you lot desire to run across business lay out of matching lines you lot tin work the choice "grep -n" below command volition exhibit on which lines Error has appeared.

$ grep -n ERROR log file.

Example 10: How to practice a recursive search inwards a directory using grep inwards UNIX

If you lot desire to practice a recursive search using grep command inwards Unix at that topographic point are 2 options either work "-R" command business choice or growth directory 1 yesteryear 1 every bit shown below.

$ grep -R shop *

This command volition search for directory or file amongst the shout out stored inwards the electrical flow directory in addition to it's all sub-directory.

Bonux Examples

Now I direct maintain 2 bonus examples of grep command inwards UNIX:

11) grep command inwards UNIX tin exhibit a matching blueprint inwards color which is quite useful to highlight the matching section, to run across matching blueprint inwards color work below command.

$ grep Exception today.log --color

You tin also practice alias grep='grep --color' inwards your bash_profile file to avoid typing --color every time.

12) There are iii versions of grep command inwards UNIX  "grep,  fgrep, in addition to egrep". `fgrep' stands for Fixed `grep', `egrep' Extended `grep'


And, hither is a prissy summary of all the grep commands you lot direct maintain learned thus far. You tin accept the impress out of this slide in addition to Julia Evans diagram I direct maintain shared before to give-up the ghost on these grep commands handy.





These examples of grep command inwards UNIX are something which I work on a daily basis; I direct maintain seen the most sophisticated work of grep amongst a regular expression. I volition listing some to a greater extent than examples of grep command inwards UNIX every bit I come upwards across in addition to honor useful to share.

As per my sense having a proficient agree on grep in addition to UNIX honor command amongst cognition of regular facial expression volition move keen for your twenty-four hr menses to twenty-four hr menses life if you lot require to expect log files or config files or require to practice production back upwards on electronic trading systems or whatever other sort of organization which is running on UNIX.

This listing of grep command inwards UNIX is yesteryear no agency consummate in addition to I expect forwards from you lot guys to percentage how you lot are using grep command inwards UNIX.

If you lot similar this article, you lot may honor the next UNIX tutorials also interesting:

• How Linux works? What every SuperUser should know
• 10 illustration of networking command inwards Unix
• How to improve speed in addition to productivity inwards Unix
• Difference betwixt a Hard link in addition to soft link inwards Unix
• 10 Example of tar commands inwards Unix
• Unix Command Tutorial: File in addition to Directory Permissions basics
• How to acquire an IP address from hostname inwards Linux
• The Linux command line: a consummate introduction

Further Learning
Linux Command Line Basics
Linux Command Line Interface (CLI) Fundamentals
Learn Linux inwards five Days in addition to Level Up Your Career

Thanks for reading this article thus far. If you lot similar these grep command examples inwards Linux in addition to then delight percentage amongst your friends in addition to colleagues. If you lot direct maintain whatever questions or feedback in addition to then delight drop  a note. 

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