Commands using awk (1,418)

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Show exit status of all portions of a piped command eg. ls |this_doesn't_exist |wc

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

list block devices
Shows all block devices in a tree with descruptions of what they are.

list and sort files by size in reverse order (file size in human readable output)
This command list and sort files by size and in reverse order, the reverse order is very helpful when you have a very long list and wish to have the biggest files at the bottom so you don't have scrool up. The file size info is in human readable output, so ex. 1K..234M...3G Tested with Linux (Red Hat Enterprise Edition)

Sort a character string
Sorts a character string, using common shell commands.

backup all your commandlinefu.com favourites to a plaintext file
Usage: clfavs username password num_favourite_commands file_in_which_to_backup

Display IP : Count of failed login attempts
The lastb command presents you with the history of failed login attempts (stored in /var/log/btmp). The reference file is read/write by root only by default. This can be quite an exhaustive list with lots of bots hammering away at your machine. Sometimes it is more important to see the scale of things, or in this case the volume of failed logins tied to each source IP. The awk statement determines if the 3rd element is an IP address, and if so increments the running count of failed login attempts associated with it. When done it prints the IP and count. The sort statement sorts numerically (-n) by column 3 (-k 3), so you can see the most aggressive sources of login attempts. Note that the ':' character is the 2nd column, and that the -n and -k can be combined to -nk. Please be aware that the btmp file will contain every instance of a failed login unless explicitly rolled over. It should be safe to delete/archive this file after you've processed it.

Bash logger

Search inside a folder of jar/zip files
Great for finding which jar some pesky class is hiding in!

find directory with most inodes/files
Find which directory in one filesystem that contains most inodes or files.


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