Popular recipes tagged "bash" but not "shell"

Collection Pipeline in Python (Python)

2016-03-16T14:45:02-07:00

Python recipe 580625 by Steven D'Aprano (bash, filter, map, pipe, pipline).

A powerful functional programming technique is the use of pipelines of functions. If you have used shell scripting languages like bash, you will have used this technique. For instance, to count the number of files or directories, you might say: ls | wc -l. The output of the first command is piped into the input of the second, and the result returned.

We can set up a similar pipeline using Lisp-like Map, Filter and Reduce special functions. Unlike the standard Python map, filter and reduce, these are designed to operate in a pipeline, using the same | syntax used by bash and other shell scripting languages:

>>> data = range(1000)
>>> data | Filter(lambda n: 20 < n < 30) | Map(float) | List
[21.0, 22.0, 23.0, 24.0, 25.0, 26.0, 27.0, 28.0, 29.0]

The standard Python functional tools is much less attractive, as you have to write the functions in the opposite order to how they are applied to the data. This makes it harder to follow the logic of the expression.

>>> list(map(float, filter(lambda n: 20 < n < 30, data)))
[21.0, 22.0, 23.0, 24.0, 25.0, 26.0, 27.0, 28.0, 29.0]

We can also end the pipeline with a call to Reduce to collate the sequence into a single value. Here we take a string, extract all the digits, convert to ints, and multiply:

>>> from operator import mul
>>> "abcd12345xyz" | Filter(str.isdigit) | Map(int) | Reduce(mul)
120

Obfuscation In Bash Shell. (Bash)

2014-12-19T20:01:30-08:00

Bash recipe 578986 by Barry Walker (apple, bash, macbook_pro, obfuscation).

IMO, the immense power of the shell...

Please let me know if there is any other human readable language that can do this...

The DEMO code below was an idea I formed to see how to make a bash script very difficult to hack.

Everything in it is made easy to read so as to see this idea working.

It uses bash variables ONLY and although I have used bash loops to create the variables in this DEMO you could create your own set of variables and 'source' them to the the obfuscated code before running the main body of the code.

It also goes without saying that you could obfuscate the changing of any or all the variable allocations at any time AFTER the code runs to make it even more obfuscated and as may times as you wish...

I would be seriously difficult to actually write a lsrge bash app' using this method but boy oh boy would it be fun?!?

Testbed:- Macbook Pro, OSX 10.7.x and above, using default bash terminal...

LBNL, yeah I am aware of 'eval' but as it is obfuscated and can have as many obfuscated variables as I wish allocated to it then why worry... ;o)

Enjoy finding simple solutions to often very difficult problems...

Bazza...

Get external IP & geolocation in bash. (Bash)

2014-11-30T00:46:28-08:00

Bash recipe 578972 by manu (bash, geocoding, geolocation). Revision 2.

Very simple way to get external IP and geolocation uysing dig and geoiplookup.

dig is cool to obtain my external IP and I use geoiplookup to convert IP to location. You need geoip-bin and, geoip-database (and/or geoip-database-contrib and geoip-database-extra). In Debian, database seems update monthly.

It's just a tip.

A Fun Perfect Square Checker Using Integer Arithmetic Only... ;o) (Bash)

2014-09-16T22:27:04-07:00

Bash recipe 578934 by Barry Walker (arithmetic, bash, check, checker, cygwin, macbook_pro, math, mathematics, perfect, root, square).

A recent Python upload here gave me the inspiration to do a bash version... This is a little tongue-in-cheek but an enjoyable bit of fun.

It took around 11 seconds to prove 90000000000 had a perfect square of 300000...

It is a stand alone program and has a degree of INPUT error correction...

It was done on a MacBook Pro, OSX 10.7.5, default bash terminal and should work on Linux flavours but it is untested...

Enjoy finding simple solutions to often very difficult problems...

Bazza...

Simple Bash Text Mode Sine Curve Generator. (Bash)

2014-08-12T20:57:39-07:00

Bash recipe 578921 by Barry Walker (apple, bash, cygwin, graph, linux, macbook_pro, text). Revision 2.

This bash script is a taster for a kids level, audio, text mode, sweep generator. The code just creates a single cycle of a quantised sine curve inside an 80 x 24 bash terminal. This will be the calculator for a sinewave sweep generator from about 50Hz the 12KHz... The code tells you more and the display is in comments at the end...

A Bash Beep Command For OSX 10.7+... (Bash)

2014-02-27T19:36:17-08:00

Bash recipe 578837 by Barry Walker (apple, audio, bash, beep, error_beep, error_sound, linux, macbook_pro, sound).

This small bash script generates an 8044 byte 1KHz sinewave wave file and immediately plays it. The file created is a _pure_ sinewave and lasts for 1 second. It uses the default "afplay" command to run the generated file.

It was designed around an Apple Macbook Pro but using "aplay" it might even work on other *nix flavours from the command line. I have not bothered to try it as this was purely for my MB Pro.

The wave file can be found as "/tmp/sinewave.wav" during the working session(s) and can be saved anywhere of your choice.

Enjoy...

(Watch for word wrapping etc...)

Bazza.

Pseudo-3D effect in text mode... (Bash)

2013-09-10T21:23:58-07:00

Bash recipe 578655 by Barry Walker (3d, apple, bash, color, colour, display, linux, macbook_pro, text).

This is just a simple DEMO to display a pseudo-3D effect using a bash script. It generates a recessed box and a button and writes some thext inside bot.

There are two pieces of code, one for Linux, and one for OSX 10.7.5...

The Linux version also works on OSX 10.7.5 but is harder to see so a near identical version using the default OSX terminal colours was craeted instead.

You will have to split the two code pieces up yourself to run...

Enjoy finding simple solutions to often very difficult problems...

Bazza...

Bash style commands (Bash)

2013-08-22T13:05:29-07:00

Bash recipe 578648 by greg zakharov (bash, cmd).

This is just a concept. To import bash style commands use "script.cmd /bash", to get the list of imported commands use "script.cmd /map"

Bash style commands (Batch)

2013-08-22T13:06:33-07:00

Batch recipe 578649 by greg zakharov (bash, cmd).

This is just a concept. To import bash style commands use "script.cmd /bash", to get the list of imported commands use "script.cmd /map"

A FUN Bash Shell Bomb-Out Error Sound... (Bash)

2013-07-14T19:31:13-07:00

Bash recipe 578605 by Barry Walker (apple, audio, bash, error_beep, error_sound, linux, macbook_pro, sound, sound_exchange, sox).

Do you remember the Bomb-Out icon(s) that appeared on some computers' SW and HW many years ago...

Well this is a matching sound to go with it and can be used as a critical error sound.

It sounds like a bomb being dropped from an aeroplane and is purely a shell sript only.

It is set up to run SOund eXchange, SOX, but just by editing the code "/dev/dsp" can be used instead.

Read the code for more informastion.

Enjoy...

Bazza...

Bash Script For An Oscilloscope... (Bash)

2013-06-19T19:06:50-07:00

Bash recipe 578570 by Barry Walker (anim, audio, audioscope, bash, oscilloscope, scope, script, sound_exchange, sox, terminal).

This code is the latest as of 19-06-2013. It is an AudioScope designed around a Macbook Pro 13" of which only has ONE microphone input. It works under Linux variants too. Read the code for much more info.

It was my way of learning Bash scripting.

It is resident here at this site:-

http://www.unix.com/shell-programming-scripting/212939-start-simple-audio-scope-shell-script.html

It started off as a fun idea and is now becoming a very serious project.

As it stands this is fully working but it is uncalibrated and this is where it will stay on this site.

As the above site is the host then all future uploads will be there...

To do list...

DC input. [1] DC polarity. [1] 2 more Internal sync modes. External triggering. Zoom facility - if possible in text mode. Vertical calibration. [2] Frequency measurement. {3] (Others.)

[1] I have simple HW built as an idea but yet to prove it... [2] Preliminary HW built but not yet used. Calibration SW and circuit(s) to be built into script as it progresses. [3] I already have a working script but not completely satisfied at it at this point...

I am noing to say much else except that it has already been given a 5 star rating on the above UNIX site...

As it stands this code is entirely Public Domian and you may do with it as you please...

Enjoy something completely different using Bash scripting...

Finally the code defaults to a DEMO mode which requires no HW access at all but everything is still functional...

__Thoroughly__ read the code for more information...

As a circuit is inside the script then it is best viewed in plan text mode.

Bazza, G0LCU.

A DEMO 6 Bit At A Glance Colouerd Bargraph Generator. (Bash)

2013-01-16T12:26:55-08:00

Bash recipe 578391 by Barry Walker (analogue, anim, apple, bargraph, bash, beep, color, colour, demo, display, generator, linux, macbook_pro). Revision 2.

This code generates a horizontal coloured real time bargraph generator anim for a Macbook Pro 13 inch, OSX 10.7.5, using the default standard Terminal only.

It is UNTESTED on Linux variants but I would like any successful Linux tryers to make a comment in the comments section and tags will be added accordingly otherwise I will assume it does NOT work on other UNIX like variants.

It is a derivative of my 7 bit bargraph generator for Python on this site elsewhere.

The Terminal colours WILL be changed on running but it is simple to return it back to its original state.

Read the code for more information.

Enjoy, (and a Happy New Year)...

Bazza, G0LCU...

Bash completed man and info pages generation (Python)

2011-08-24T03:14:13-07:00

Python recipe 577854 by Josh D (a, all, and, bash, be, command, completed, consume, file, first, generation, get, in, info, line, man, modify, must, only, pages, possibilties, possiblities, py, python, run, script, so, tab, terminal, the, this, to). Revision 6.

The script it self is very self explaining - the task is simple. *NIX only unless with cygwin perhaps?

To start this open a terminal and strike the "Tab" key to get all possibilities (strike y, and strike the space key alot). Select all then Copy and save in "comms.txt" Modify the file so ONLY the possiblities consume a line; no prompts or extra newlines. (first line must be a command, the last line must be a command)

Save the file ("~/Documents/bashing/comms.txt" is my path) then run this script in "~/Documents/bashing/".

This generates two (2) files: "bash_help_man.sh", "bash_help_info.sh".

Then it runs these files: "bash bash_help_man.sh", "bash bash_help_info.sh".

This produces 2 files for every command (every line) in "comms.txt". All manpages are wrote in "mans/", all infopages are wrote in "infos/"

There is now alot of files to read and organize; lets separate these by size. Directories are under1kb, under2kb, etc.

Once complete do as you wish the files less than 128 kb; these files are COPIED into there new respective home, I repeat COPIED.

The files 128 kb and higher ARE NOT copied to anywhere!

Basic Linux Menu (Bash)

2010-10-23T05:40:18-07:00

Bash recipe 577437 by Jonathan Fenech (bash, basic, linux, menu).

A basic Linux menu which can do the following:

Display Files and Directory's
Remove Files Displayed
Copy Files Displayed
Make Directory

scan db to login the ssh servers (Bash)

2010-03-16T13:11:17-07:00

Bash recipe 576877 by J Y (awk, bash). Revision 2.

awk with parameters passed from bash

How to detect the Linux distribution from an init.d script (Bash)

2010-03-16T13:24:22-07:00

Bash recipe 576676 by Gui R (bash, redhat). Revision 2.

There is no trivial way to know what Linux you are running. Red Hat, SuSE, etc., each distribution has a different way to tell what version is installed.