Commands using awk

This command will list a CSV list of infected files detected by clamav through squidclamav redirector.

Parses tektronic given csv files for both channel 1 and channel 2 and joins them together. Can be easily used by gnuplot after that.

Useful in scripts while you just need an IP address in a variable.

I use this on debian testing, works like the other sorted du variants, but i like small numbers and suffixes :)

kills all pids matching the search term of "PROCESS". Be careful what you wish for :)

Ran as the postgres user, dumps each database individually. It dumps with the create statements as well, so you can just 'zcat $x-nightly.dmp.gz | psql' to reimport/recreate a database from a backup.

Note that the file at the given path will have the contents of the (still) deleted file, but it is a new file with a new node number; in other words, this restores the data, but it does not actually "undelete" the old file.

I posted a function declaration encapsulating this functionality to http://www.reddit.com/r/programming/comments/7yx6f/how_to_undelete_any_open_deleted_file_in_linux/c07sqwe (please excuse the crap formatting).

This finds a process id by name, but without the extra grep that you usually see. Remember, awk can grep too!

I think I could cut down the number of pipes here, any suggestions?

This is a nice way to kill processes.. the example here is for firefox!!! substitute firefox for whatever the process name is...

Ever logged into a *nix box and needed to know which webserver is running and where all the current access_log files are? Run this one liner to find out. Works for Apache or Lighttpd as long as CustomLog name is somewhat standard. HINT: works great as input into for loop, like this:

Very useful for triage on unfamiliar servers!

convenience.

Useful to check DDoS attacks on servers.

This command takes the output of the 'last' command, removes empty lines, gets just the first field ($USERNAME), sort the $USERNAMES in reverse order and then gives a summary count of unique matches.

Sometimes, in a shell script, you need a random number bigger than the range of $RANDOM. This will print a random number made of four hex values extracted from /dev/urandom.

This is a 'killall' command equivalent where it is not available.

Prior to executing it, set the environment variable USERNAME to the username, whose processes you want to kill or replace the username with the $USERNAME on the command above.

Side effect: If any processes from other users, are running with a parameter of $USERNAME, they will be killed as well (assuming you are running this as root user)

[-9] in square brackets at the end of the command is optional and strongly suggested to be your last resort. I do not like to use it as the killed process leaves a lot of mess behind.

This command specifies the size in Kilobytes using 'k' in the -size +(N)k option. The plus sign says greater than. -exec [cmd] {} \; invokes ls -l command on each file and awk strips off the values of the 5th (size) and the 9th (filename) column from the ls -l output to display. Sort is done in reversed order (descending) numerically using sort -rn options.

A cron job could be run to execute a script like this and alert the users if a dir has files exceeding certain size, and provide file details as well.

The $2, $3, $4 fields are arbitrary but note that the first field starts from $2 and the last field is $NF-1. This is due to the fact that the leading and trailing quotes are treated as field delimiters.

changes the PS1 to something better than default.

[username.hostname.last-2-digits-of-ip] (current directory)

For quick validation of folder's file-contents (structure not taken into account) - I use it mostly to check if two folders' contents are the same.