find / -xdev -perm -4000 -exec ls -l {} \;
find / -xdev -perm -o+w -and -not \( -type l -or -type s -or -perm -o+t \) -exec ls -ld {} \;
find -not -empty -type f -printf "%s\n" | sort -rn | uniq -d | xargs -I{} -n1 find -type f -size {}c -print0 | xargs -0 md5sum | sort | uniq -w32 --all-repeated=separate
find /var/log/ -type f -name '*.log' -ctime +60 -exec rm -f {} \;
find / -mmin +60 -type f
find . -type f -exec grep -l '.\{80\}' {} \;
/bin/nice -19 /usr/bin/find / -type f -print 2>/dev/null | egrep -r '/core\.[0-9]{2,}' | /usr/bin/xargs ls -l
echo $((($(date +%s) - $(stat -c %Y -- /etc/hosts)) / 86400)) days
classical side-by-side comparison
diff -y file1 file2
vimdiff file1 file2
ssh user@host cat /path/to/remotefile | diff -y /path/to/localfile -