grep not

Shell
# EXAMPLE: displays any lines that contain either "include this string" or "this works too" 
egrep "include this string|this works too" *

# SYNTAX:
# egrep "<pattern-1>|<pattern-2>" *

# egrep is combined with the "|" character (pipeline: normally the shift alternative to the "\" on the keyboard)# EXAMPLE
grep -v "irrelevant string" *

# SYNTAX
# grep -v "<string-you-do-not-want>" *
Source

Also in Shell: