Commands by rekky (1)

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Write comments to your history.
A null operation with the name 'comment', allowing comments to be written to HISTFILE. Prepending '#' to a command will *not* write the command to the history file, although it will be available for the current session, thus '#' is not useful for keeping track of comments past the current session.

delete multiple files with spaces in filenames (with confirmation)
ls -Q will show the filenames in quotes. xargs -p rm will print all the filenames piped from ls -Q and ask for confirmation before deleting the files. without the -Q switch, if we have spaces in names, then the files won't be deleted.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Get a qrcode for a given string

Get playlist for Livestream on YouTube

Sort IPV4 ip addresses

Merge PDFs with Ghostscript wrapped in a function
This is an expansion on a previous entry, which I've wrapped in a function and placed in my profile. The "$@" is a positional parameter, much like "$*", but the parameters are passed on intact, without interpretation or expansion; so you can simply call the function like this: mergepdf * This will output a merged PDF of all PDFs in the current directory. Alternatively, you can simply list them like so: mergepdf 00.pdf 01.pdf 02.pdf ... N.B. Passing a wildcard will merge all PDFs in the current directory in name order, e.g. 00.pdf 01.pdf aa.pdf ab.pdf

Open Port Check
also could specify port number: lsof -ni TCP:80

scp a good script from host A which has no public access to host C, but with a hop by host B
middlehost allows ssh access from where you are but not securehost. Use nice ssh piping to simulate scp through A => B => C setting up the shell function if left as an exercise for the reader. ;-) Agent forwarding should avoid password typing.

Get your external IP address ( 10 characters long )
Shortest url to a external IP-service, 10 characters.


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