Commands by ehmicky (1)

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Convert IP octets to HEX with no dots.
Converts IP octets to hex using printf command. Useful for generating pxeboot aliases in the pxelinux.cfg folder.

add a backup (or any other) suffix to a file
Very helpful when you've got complex filenames and needs to change just some small parts of it. Renaming a file called "i-made-a-small-typo-right-here" to "i-made-a-big-typo-right-here": $ mv -vi i-made-a-{small,big}-typo-right-here You could also copy multiple files, edit, remove, process, etc.

Kill all processes that listen to ports begin with 50 (50, 50x, 50xxx,...)
Run netstat as root (via sudo) to get the ID of the process listening on the desired socket. Use awk to 1) match the entry that is the listening socket, 2) matching the exact port (bounded by leading colon and end of column), 3) remove the trailing slash and process name from the last column, and finally 4) use the system(…) command to call kill to terminate the process. Two direct commands, netstat & awk, and one forked call to kill. This does kill the specific port instead of any port that starts with 50. I consider this to be safer.

Get AWS temporary credentials ready to export based on a MFA virtual appliance
You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token. This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use: `awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'` You must adapt the command line to include: * $MFA_IDis ARN of the virtual MFA or serial number of the physical one * TTL for the credentials

Create a script of the last executed command
Sometimes commands are long, but useful, so it's helpful to be able to make them permanent without having to retype them. An alternative could use the history command, and a cut/sed line that works on your platform. $history -1 | cut -c 7- > foo.sh

All IP connected to my host
find all computer connected to my host through TCP connection.

Make vim open in tabs by default (save to .profile)
I always add this to my .profile rc so I can do things like: "vim *.c" and the files are opened in tabs.

Quickly generate an MD5 hash for a text string using OpenSSL

check the status of 'dd' in progress (OS X)
While a dd is running in one terminal, open another and enter the while loop. The sample output will be displayed in the window running the dd and the while loop will exit when the dd is complete. It's possible that a "sudo" will need to be inserted before "pkill", depending on your setup, for example: $ while pgrep ^dd; do sudo pkill -INFO dd; sleep 10; done

Ultimate current directory usage command
Based on the MrMerry one, just add some visuals to differentiate files and directories


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