AWK
@ https://www.grymoire.com/Unix/Awk.html
Guide to AWK, a versatile programming language for working on files.
sed
@ https://www.gnu.org/software/sed/manual/sed.html
Guide to sed, a steam editor. sed is used to perform basic text transformations on an input stream.
grep
@ https://www.gnu.org/software/grep/manual/grep.html
Guide to grep, a pattern matching tool to search files.