find

find . -name Root -exec perl -pi -e 's/\/usr\/local\/cvsroot/\/cvsweb/' {} \;  
find . -type f -name "*.pdf" -print | xargs -t rm Delete a lot of files with the extension pdf and trace that.
find / -type f \( -perm -04000 -o -perm -02000 \) \-exec ls -lg {} \; Find all SUID/SGID programs on your system:
find / -type f \( -perm -2 -o -perm -20 \) -exec ls -lg {} \; Locate all group & world-writable files on your system, use the command:
find / -type d \( -perm -2 -o -perm -20 \) -exec ls -ldg {} \; Locate all group & world-writable directories on your system, use the command:
find ~ -size +1000k Find all files in your home directory with at least 1000 kilobytes in size.
find ~ -size -100b Find all files in your home directory that are less than 100 bytes in size.
find ~ -empty Find all empty files in your home directory.
find ~ -mtime -1 Find all files in your home directory that were modified with the past 24 hours.
find ~ -mmin -5 Find all files in your home directory that were modified with the past 5 minutes.
find ~ -mtime 1 -daystart Find all files in your home directory that were modified yesterday.
find ~ -mtime +30 Find all files in your home directory that were modfified 30 days or longer ago.
find ~ -mtime 10 -mtime -30 Find all files in your home directory that were modfified from 10 to 30 days ago.
find $home -newer /backups/last-backup Find all the files in your home directory that are newer than /backups/last-backup.

Technology: