[Linux](EN) AND, OR, NOT condition usage in grep command

Use AND, OR, NOT condition in grep command

Environment and Prerequisite

• Linux base system
• Bash shell(/bin/bash)

What is grep?

grep

• grep: Print lines that match patterns.

# Basic Usage
$ grep [OPTIONS] PATTERN [FILE...]
$ grep [OPTIONS] [-e PATTERN | -f FILE] [FILE...]

• File name and pattern usage

# Example 1
$ grep pattern filename

• Pipe and pattern usage

# Example 2
$ cat << EOF | grep example
> test
> example
> example1
> example+test
> this
> is
> EOF
example
example1
example+test

AND Condition Usage

Purpose

• Print lines which contain all patterns.

(Method1) Use multiple grep

• Use multiple grep with pipe

$ cat test.txt | grep pattern1 | grep pattern2

(Method2) Use -E option

• Use -E option.
• You can use Regular Expression in grep with -E option. Like below, it prints lines which contain pattern1 and pattern2. However order will be pattern1 -> pattern2.

$ grep -E grep "pattern1.*pattern2"

• Following example will print all lines which contain both pattern1 and patter2 without any order.

$ grep -E grep "pattern1.*pattern2|pattern2.*pattern1"

OR Condition Usage

Purpose

• Print lines which contain at least one pattern.

(Method1) Use -e option

$ cat test.txt | grep -e pattern1 -e pattern2

(Method2) Use -E option

$ cat test.txt | grep -E "pattern1|pattern2"

NOT Condition Usage

Purpose

• Print lines which does not match pattern.

(Method) Use -v option

# Example 1
$ cat test.txt | grep -v pattern

# Example 2
$ cat test.txt | grep -v pattern1 | grep -v pattern2

Reference

• https://www.thegeekstuff.com/2011/10/grep-or-and-not-operators/
• http://linuxcommand.org/lc3_man_pages/grep1.html