lsb_release -a; # tested on
Description:	Debian GNU/Linux 10 (buster)

# output all lines that containt KEYWORD
grep KEYWORD file.txt

# output all lines that DO NOT containt KEYWORD (search inverted)
grep -v KEYWORD file.txt
#       -v, --invert-match
#              Invert the sense of matching, to select non-matching lines.

# subsearch, first search for "this" than in that output search for "that"
# show all lines that have this and that
output of a command | grep "this" | grep "that"

# grep multiple: show all lines that have either or that 
output of a command | grep -e 'this' -e 'that'

# thus if the user wants to filter out all lines containing KEYWORD
grep -v KEYWORD file.txt > file.without.KEYWORD.txt

# if the user wants to filter out all lines that start with char x
# show all lines that start with x
grep "^[x]" file.txt | less
# hide all lines that start with x
grep -v "^[x]" file.txt | less

# search for FILENAME, and pipe result to less
find / -iname "*FILENAME*"|less

# inside less it is possible to type
/another-search-pattern

# this way is convenient to find files by filename with two search patterns

# filter out all lines of man that contain the keyword mail
man mail|grep --color mail

liked this article?

  • only together we can create a truly free world
  • plz support dwaves to keep it up & running!
  • (yes the info on the internet is (mostly) free but beer is still not free (still have to work on that))
  • really really hate advertisement
  • contribute: whenever a solution was found, blog about it for others to find!
  • talk about, recommend & link to this blog and articles
  • thanks to all who contribute!
admin