Basics

Brace expansion

  1. echo {1..10} # 1 2 3 4 5 6 7 8 9 10
  2. echo {1..10..3} # 1 4 7 10
  3. touch {file1, file2, file3}; ls # file1 file2 file3
  5. touch file_{1..10}; ls # file1 file2 file3 ... file10

Padding with zero

  1. touch file_{01..100}; ls # file01 file02 .. file100
  1. ls -l | wc -l  # wordcount all the files

more is cat with pagination.

  1. ls -l | more

Redirect

use >:

  • 1 is stdout
  • 2 is sterr
  • & is stdout and sterr

grep

Enable color

grep --color=auto jorge auth.log

To enable it all the time use:
export GREP_OPTIONS='--color=auto'

Exclude directory

grep -R --exclude-dir=node_modules 'some pattern' /path/to/search

Include lines after the find

  1. grep -A2 textToSearch jsx/

-A2 will return the two lines after.
-B2 will return the two previous lines.
-C2 will return two lines before and after.

awk Command

This will print only the 12th word on every sentence:

  1. grep -i break-in auth.log | awk {'print $12'}

Another useful command: sed