The command could show you all conecctions if you skip "grep ESTABLISHED" Show Sample Output

Searches all log files (including archived bzip2 files) for invalid user and PAM authentication errors, both of which are indicative of brute force attempts at logging into computer. A list of all unique IP addresses and domain names is appended to hosts.deny. The command (and grep error messages) will work on Mac OS X 10.6, small adjustments may be needed for other OSs.

Revised approach to and3k's version, using pipes and read rather than command substitution. This does not require fiddling with IFS when paths have whitespace, and does not risk hitting command-line size limits. It's less verbose on the missing files, but it stops iterating at the first file that's missing, so it should be definitely faster. I expanded all the qlist options to be more self-describing.

perl-less way

I'm sure there's a more elegant sed version for the tr + grep section.

Updated according to flatcap's suggestion, thanks!

Show Sample Output

This command does a tally of concurrent active connections from single IPs and prints out those IPs that have the most active concurrent connections. VERY useful in determining the source of a DoS or DDoS attack. Show Sample Output

Improvement of the command "Find Duplicate Files (based on size first, then MD5 hash)" when searching for duplicate files in a directory containing a subversion working copy. This way the (multiple dupicates) in the meta-information directories are ignored. Can easily be adopted for other VCS as well. For CVS i.e. change ".svn" into ".csv": find -type d -name ".csv" -prune -o -not -empty -type f -printf "%s\n" | sort -rn | uniq -d | xargs -I{} -n1 find -type d -name ".csv" -prune -o -type f -size {}c -print0 | xargs -0 md5sum | sort | uniq -w32 --all-repeated=separate Show Sample Output

count the times a domain appears on a file which lines are URLs in the form http://domain/resource. Show Sample Output

list top committers (and number of their commits) of svn repository. in this example it counts revisions of current directory. Show Sample Output

This command will allow to search for duplicate processes and sort them by their run count. Note that if there are same processes run by different users you'll see only one user in the result line, so you'll need to do: ps aux | grep <process> to see all users that run this command. Show Sample Output

This works on Mac OS X using the `md5` command instead of `md5sum`, which works similarly, but has a different output format. Note that this only prints the name of the duplicates, not the original file. This is handy because you can add `| xargs rm` to the end of the command to delete all the duplicates while leaving the original.

Uses line-porcelain in git blame, which makes it easier to parse the output.

# find assumes email files start with a number 1-9 # sed joins the lines starting with " " to the previous line # gawk print the received and from lines # sort according to the second field (received+from) # uniq print the duplicated filename # a message is viewed as duplicate if it is received at the same time as another message, and from the same person. The command was intended to be run under cron. If run in a terminal, mutt can be used: mutt -e "push otD~=xq" -f $folder Show Sample Output