This command shows a sorted list of the IP addresses from which there have been authentication errors via SSH (possible script kiddies trying to gain access to your server), it eliminates duplicates so it's easier to read, but you can remove the "uniq" command at the end, or even do a "uniq -c" to have a count of how many times each IP address shows in the log (the path to the log may vary from system to system) Show Sample Output

sort command can sort month-wise (first three letters of each month). See the sample output for clarification. Sorting Stable ? NO. Take note if that matters to you. Sample output suggests that sort performs unstable sorting (see the relative order of two 'feb' entries). 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.

* grep -i leaves only mp3 files (case insentitive) * sort -R randomizes list (may use GNU 'shuf' instead). * the sed command will add double quotes around each filename (needed if odd characters are present)

Works on most unixes, on OpenBSD replace the "-g" parameter at the sort with a "-n".

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

I had the problem that our monitoring showed that the "/" filesystem is >90% full. This command helped me to find out fast which subdirs are the biggest. The system has many NFS-mounts therefore the -x.

Need admin right to run dpkg-query Show Sample 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

I like it sorted... 2> /dev/null was also needless, since our pipes already select stdin, only.

Show sizes of all files and directories in a directory in size order. du -hs * | sort -hr for reverse order. Taken from http://serverfault.com/questions/62411/how-can-i-sort-du-h-output-by-size Show Sample Output

Get the longest match of file extension (Ex. For 'foo.tar.gz', you get '.tar.gz' instead of '.gz') Show Sample Output

list the top 15 folders by decreasing size in MB Show Sample Output

This command is useful for finding out which directories below the current location use the most space. It is summarised by directory and excludes mounted filesystems. Finally it is sorted by size. Show Sample Output

Analyze an Apache access log for the time period with most activity and display the hit count, requesting IP and the timestamp. May help detect a brute force dos attack.

Use the AWS CLI tools to generate a list instances, then pipe them to JQ to show only their launch time and instance id. Finally use sort to bring them out in runtime order. Find all those instances you launched months ago and have forgotten about. Show Sample Output

IP addresses and number of connections connected to port 80. Show Sample Output

I tried a few curses based mp3 players for playing back choir practice songs for my wife. Unfortunately none of the ones I tried were capable of scrubbing a track. Firefox saves the day.