egrep
Extended version of grep.
fgrep
Searches files for literal words.
find
Searches the system for filenames.
grep
Searches files for text patterns.
locate
Faster version of find; however, it depends on a database that is periodically updated by the weekly periodic job. If the database is out of date, find is more accurate.
sort
Sorts a file (use -n for numeric sorting and -u to eliminate duplicates).
strings
Searches binary files for text patterns.
uniq
Reports or filters duplicate lines in a file.
unzip
Extracts files from a Zip archive.
zgrep
Searches compressed files for text patterns.
zip
Creates a Zip archive.