Commands for the wicked (109)

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sed : using colons as separators instead of forward slashes
Having to escape forwardslashes when using sed can be a pain. However, it's possible to instead of using / as the separator to use : . I found this by trying to substitute $PWD into my pattern, like so $ sed "s/~.*/$PWD/" file.txt Of course, $PWD will expand to a character string that begins with a / , which will make sed spit out an error such as "sed: -e expression #1, char 8: unknown option to `s'". So simply changing it to $ sed "s:~.*:$PWD:" file.txt did the trick.

Quickly display a string as Qr Code
Takes the first argument (string) and display a Qr code version of that.

a for loop with filling 0 format, with seq
seq allows you to format the output thanks to the -f option. This is very useful if you want to rename your files to the same format in order to be able to easily sort for example: $for i in `seq 1 3 10`; do touch foo$i ;done And $ls foo* | sort -n foo1 foo10 foo4 foo7 But: $for i in `seq -f %02g 1 3 10`; do touch foo$i ;done So $ls foo* | sort -n foo01 foo04 foo07 foo10

socat TCP-LISTEN:5500 EXEC:'ssh user@remotehost "socat STDIO UNIX-CONNECT:/var/run/mysqld/mysqld.sock"'
Listens on local port 5500 and connects to remotehost with username user to tunnel the given socket file. Will work with anything, but can be useful if there's a need for a local application to connect with a remote server which was started without networking.

Monitor RAID IO Usage
Shows the IO of the raid sync

Quickly analyze apache logs for top 25 most common IP addresses.
This command is much quicker than the alternative of "sort | uniq -c | sort -n".

Replace duplicate files by hardlinks
This variation can handle file paths containing spaces.

Open Remote Desktop (RDP) from command line having a custom screen size
This example uses xfreerdp, which builds upon the development of rdesktop. This example usage will also send you the remote machine's sound.

Go to the next sibling directory in alphabetical order
Sometimes you have to browse your way through a lot of sub-directories. This command cd to the next sub-directory in alphabetical order. For example, if you have the directories "lectures/01-intro", "lectures/02-basic", "lectures/03-advanced" and so on, and your PWD is "02-basic", it jumps to "03-advanced".

ROT13 using the tr command


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