Linux-find-file

Which and Whereis locate man pages and locations of binary files for a specific program.
$ which pwd
$ whereis pwd

Locate uses database that needs updated (by cron)
$ locate pwd
$ updatedb ← updates locate database
$ locate kernel | grep /usr ← find “kernel” in path or file name within the /usr folder

Find
$ find <begining location> -name '<string>' ← example find . -name 'cron*' will find all files within current and recursive that contain 'cron*' in the name of the file or content within the file
type f ← parameter will restrict to only files named ...
type d ← find only directories named …
perm 777 ← find all files with permissions 777
$ find /home -perm 777 -exec chmod 555 {} \; ← modify all files found with 777 permission, {} = foreach, \; = complete the line
$ find  / -mtime +1 ← find all files modified within last day
$ find  / -a +1 ← find all files accessed within
$ find / -group nameOfGroup ← find all files owned by group
$ find . -size 1M ← find all files that are 1 megabyte