Grep command is used for searching the content of file returning the result.

• Basic syntax: grep -in "search_term" filename
  • -n : gives the line-number of matching term in a file
  • -i : Ignore case
• Search in directory: grep -nr search_term directory
  • -r : searches recursively in given directory
• List all file with the search_term: grep -l "search_term" \*
  • -l : Input needs to be list of files

• List all lines not/invert-match with the search_term: grep -nv "search_term" filename

• List all file with the search_term in given directory: grep -lr search_term .
  • . represents current directory
• Select only matches that exactly match the whole line: grep -xr tabular ..
  • .. represents the parent directory
• Exclude certain dir: grep --exclude-dir "_site" -nr "search_text" ."

Bonus command:

• Using find, xargs and grep for faster search: find . -iname *.py | xargs grep --color 'search-term'
  • It list all the python(.py) file and greps through each of the file
  • This is faster, if you’ve large directory to search and you know which type of file you need.
  • find and grep is powerful combination to use.

Reference:

• http://www.uccs.edu/~ahitchco/grep/