What are the differences among grep awk sed

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Possible Duplicate    What are the differences between Perl  Python  AWK and sed    What is the difference between sed and awk        Maybe not a very specific question  but I am confused about the differences between grep  awk and sed in terms of their role in Unix Linux system administration and text processing

User · Answer

Grep is useful if you want to quickly search for lines that match in a file. It can also return some other simple information like matching line numbers, match count, and file name lists.

Awk is an entire programming language built around reading CSV-style files, processing the records, and optionally printing out a result data set. It can do many things but it is not the easiest tool to use for simple tasks.

Sed is useful when you want to make changes to a file based on regular expressions. It allows you to easily match parts of lines, make modifications, and print out results. It's less expressive than awk but that lends it to somewhat easier use for simple tasks. It has many more complicated operators you can use (I think it's even turing complete), but in general you won't use those features.

User · Answer

I just want to mention a thing  there are many tools can do text processing  e g  sort  cut  split  join  paste  comm  uniq  column  rev  tac  tr  nl  pr  head  tail       they are very handy but you have to learn their options etc   A lazy way  not the best way  to learn text processing might be  only learn grep   sed and awk  with this three tools  you can solve almost 99  of text processing problems and don t need to memorize above different cmds and options       AND  if you  ve learned and used the three  you knew the difference  Actually  the difference here means which tool is good at solving what kind of problem   a more lazy way might be learning a script language  python  perl or ruby  and do every text processing with it

User · Answer

Short definition   grep  search for specific terms in a file   usage   grep This file txt Every line containing  This  Every line containing  This  Every line containing  This  Every line containing  This     cat file txt Every line containing  This  Every line containing  This  Every line containing  That  Every line containing  This  Every line containing  This    Now awk and sed are completly different than grep  awk and sed are text processors  Not only do they have the ability to find what you are looking for in text  they have the ability to remove  add and modify the text as well  and much more     awk is mostly used for data extraction and reporting  sed is a stream editor Each one of them has its own functionality and specialties    Example  Sed    sed -i  s cat dog   file txt   this will replace any occurrence of the characters  cat  by  dog    Awk    awk   print  2   file txt   this will print the second column of file txt   Basic awk usage  Compute sum average max min etc  what ever you may need     cat file txt A 10 B 20 C 60   awk  BEGIN  sum 0  count 0  OFS   t    sum   2  count    END  print  Average    sum count   file txt Average     30   I recommend that you read this book  Sed  amp  Awk  2nd Ed   It will help you become a proficient sed awk user on any unix-like environment

[linux] What are the differences among grep, awk & sed?

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