1. Archives (compress, extract and so on)
tar cvf archive_name.tar dirname/ # create a new tar archive named archive_name by packing all stuff from dirname

tar xvf archive_name.tar # extracting from existing tar archive

tar tvf archive_name.tar # view an existing tar archive
  1. grep command
grep -i "the" demo_file # search for a given string in a file

grep -r "ramesh" * # search for a given string in all files RECURSIVELY
  1. find
find -iname "MyProgram.c" # find files using file-name(case in-sensitive)

find -iname "MyCProgram.c" -exec md5sum {} \;
  1. sed – Stream editor

when copy a DOS file to Unix, one could probably find \r\n at the end of each line. the following command converts the DOS file formate to Unix file format using sed command

sed 's/.$//' filename

between '', it is regular expression, follows pattern s/{been_replaced}/{using_this_to_replace}

  1. awk – tool to process or analyze text files

the basic format of an awk command looks like this:

awk 'pattern {action}' input-file > output-file

using awk command can remove duplicated lines, print specific field from a file and so on.

awk has 8 built-in variables, you can refer to this post

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