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Archive for the ‘bash’ Category

linux – Test if a port on a remote system is reachable (without telnet) – Super User

Posted by jpluimers on 2019/01/29

Just learned that bash can do TCP and UDP itself:

Bash has been able to access TCP and UDP ports for a while. From the man page:

/dev/tcp/host/port
    If host is a valid hostname or Internet address, and port is an integer port number
    or service name, bash attempts to open a TCP connection to the corresponding socket.
/dev/udp/host/port
    If host is a valid hostname or Internet address, and port is an integer port number
    or service name, bash attempts to open a UDP connection to the corresponding socket.

So you could use something like this:

xenon-lornix:~> cat < /dev/tcp/127.0.0.1/22
SSH-2.0-OpenSSH_6.2p2 Debian-6
^C pressed here

Taa Daa!

This for systems that do not have telnet installed (Windows stopped using this a long time ago, many Linux distributions followed suit) and you cannot to use nc (also known as netcat).

–jeroen: [WayBacklinux – Test if a port on a remote system is reachable (without telnet) – Super User

Posted in *nix, *nix-tools, bash, bash, Development, Power User, Scripting, Software Development | Leave a Comment »

aha (Ansi HTML Adapter) with clickable URIs

Posted by jpluimers on 2018/10/02

aha is great to generate HTML from ANSI text (i.e. the coloured output on a Linux console).

But it doesn’t generate clickable URIs (it can’t yet by itself as it only looks one character in the future).

The thread at https://github.com/theZiz/aha/issues/20 suggested a case-insensitive regex through sed but the exact suggestion failed for a few reasons I will explain below.

First the bash alias (requires both aha and perl):

Read the rest of this entry »

Posted in *nix, *nix-tools, bash, bash, Development, Perl, Power User, RegEx, Scripting, Software Development | Leave a Comment »

pure-bash-bible/README.md – book for doing things in bash without external tools

Posted by jpluimers on 2018/09/21

[WayBack] pure-bash-bible/README.md at master · dylanaraps/pure-bash-bible · GitHub:

The goal of this book is to document known and unknown methods of doing various tasks using only built-in bash features. Using the snippets from this bible can help remove unneeded dependencies from scripts and in most cases make them faster. I came across these tips and discovered a few while developing neofetchpxltrm and other smaller projects.

The snippets below are linted using shellcheck and tests have been written where applicable. Want to contribute? Read the CONTRIBUTING.md. It outlines how the unit tests work and what is required when adding snippets to the bible.

See something incorrectly described, buggy or outright wrong? Open an issue or send a pull request. If the bible is missing something, open an issue and a solution will be found.

Via:

jeroen

Posted in *nix, *nix-tools, bash, bash, Development, Power User, Scripting, Software Development | Leave a Comment »

bash: `printf` supports `\e` just like `echo -e` does

Posted by jpluimers on 2017/11/07

Learned a few things when modifying https://github.com/gkotian/gautam_linux/blob/master/scripts/colours.sh

Note: `printf` supports emitting `ESC` (ASCII character `\033` aka `27` aka `0x1B`)as `\e` the same way that `echo` does

https://linux.die.net/man/1/printf
https://linux.die.net/man/1/echo

Format strings are at https://linux.die.net/man/3/printf
%-10s means left adjusted (aligned) string of length 10

–jeroen

via:

I was investigating how the colour definitions on my OpenSuSE system actually work internally so I added some extra output: ${TYPE} and ${COLOUR}.

Source: Show type and colour definition in addition to the rendered colour. by jpluimers · Pull Request #5 · gkotian/gautam_linux

Posted in *nix, *nix-tools, bash, bash, Development, Linux, openSuSE, Power User, Scripting, Software Development, SuSE Linux | Leave a Comment »

nojhan/liquidprompt: A full-featured & carefully designed adaptive prompt for Bash & Zsh

Posted by jpluimers on 2017/10/05

Wow: nojhan/liquidprompt: A full-featured & carefully designed adaptive prompt for Bash & Zsh

This is really useful!

via:

Sort of tanslated from the first “via” (note that “mit Alles und Scharf” is hard to translate; it’s somewhere between “everything but the kitchen sink, but done right” and “right on the money”):

Bash Prompt Overkill: https://github.com/nojhan/liquidprompt is a Bash “Prompt doing it all right”-extension, which doesn’t care how much any feature costs as we have cores, gigabytes and SSD.

Liquid Prompt automagically recognises context and enables a plethora of features in the prompt when needed based on that context.

It’s like pixie dust for your prompt.

You can configure everything, but you don’t have to: the out of the box experience is already like pixie dust for your prompt.

It works on OS X too and is part of homebrew:

$ brew install liquidprompt
==> Using the sandbox
==> Downloading https://github.com/nojhan/liquidprompt/archive/v_1.11.tar.gz
==> Downloading from https://codeload.github.com/nojhan/liquidprompt/tar.gz/v_1.11
######################################################################## 100.0%
==> Caveats
Add the following lines to your bash or zsh config (e.g. ~/.bash_profile):
  if [ -f /usr/local/share/liquidprompt ]; then
    . /usr/local/share/liquidprompt
  fi
If you'd like to reconfigure options, you may do so in ~/.liquidpromptrc.
A sample file you may copy and modify has been installed to
  /usr/local/share/liquidpromptrc-dist
Don't modify the PROMPT_COMMAND variable elsewhere in your shell config;
that will break things.
==> Summary
🍺  /usr/local/Cellar/liquidprompt/1.11: 7 files, 125.6K, built in 3 seconds
[jeroenp:~/Versioned] 10s $

–jeroen

Read the rest of this entry »

Posted in *nix, *nix-tools, Apple, bash, bash, Development, Mac OS X / OS X / MacOS, Power User, Scripting, Software Development | Leave a Comment »

 
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