Popular recipes tagged "bash" but not "script"

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

A UNIX-like "which" command for Python (Python)

2015-03-20T19:23:45-07:00

Python recipe 579035 by Vasudev Ram (bash, commandline, commands, linux, shell, unix, utilities, which).

UNIX users are familiar with the which command. Given an argument called name, it checks the system PATH environment variable, to see whether that name exists (as a file) in any of the directories specified in the PATH. (The directories in the PATH are colon-separated on UNIX and semicolon-separated on Windows.)

This recipe shows how to write a minimal which command in Python. It has been tested on Windows.

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...

Print selected text pages to PDF with Python, selpg and xtopdf on Linux (Bash)

2014-10-29T17:38:10-07:00

Bash recipe 578954 by Vasudev Ram (bash, linux, pdf, python, reportlab, shell, text, text_files, text_processing, unix).

This recipe shows how to use selpg, a Linux command-line utility written in C, together with xtopdf, a Python toolkit for PDF creation, to print only a selected range of pages from a text file, to a PDF file, for display or print purposes. The way to do this is to run the selpg utility at the Linux command line, with options specifying the start and end pages of the range, and pipe its output to the StdinToPDF.py program, which is a part of the xtopdf toolkit.

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.

Zenity Chunk Editor, creating an hashing to preserve Code Integrity. (Bash)

2013-10-22T01:30:42-07:00

Bash recipe 578693 by Patrick Riendeau (bash, debian, development, library, mint, shell, ubuntu).

It Open by default a uuid-like temporary file. There is no actual was to modify the name, but assuming the implementation of ZenityShellEval imply a limited acces to shell, you might recuperate information from shell or futur adding to transfer a name or simple renaming the uuid-like file-name... This is to prevent auto-execution of a script from canned-design by playing with without having all clearly create your shell script and/or having fully pseudo-code explained and having confirmation of your design work...

Initially, the shell Editor look like this : is:

The dependency are simple, it require My GitHub Fnct.D project, available here: [link](https://github.com/priendeau/Fnct.d) to be installed inside /etc/init.d/Fnct.D like this

git clone https://github.com/priendeau/Fnct.d /etc/init.d/Fnct.D

and loading the Lib first:

. /etc/init.d/Fnct.D/fnct_lib

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...

Two Versions Of Bash One Liner INKEY$ Functions... (Bash)

2013-03-28T17:51:32-07:00

Bash recipe 578502 by Barry Walker (bash, function, inkey, shell). Revision 2.

This is probably common knowledge to the professionals but not so much for amateurs like myself.

This is a code snippet for the equivalent of BASIC's...

LET char$=INKEY$

As the timeout parameter cannot be less than 1 second then this is the only limitation...

It is a single line function which has a variable "char"...

Read the code for more information...

There are now two versions, edit out and choose which is best for you...

DEMO - Generate A Crude 1KHz Sinewave Using A BASH Script. (Bash)

2013-03-01T19:41:47-08:00

Bash recipe 578477 by Barry Walker (audio, bash, demo, generator, linux, shell, sinewave, sound).

A very simple crude sinewave generator using a BASH script inside a Linux Terminal.

The file required is generated inside the code and requires /dev/audio to work.

Ensure you have this device, if not the download oss-compat from your OS's repository...

It lasts for about 8 seconds before exiting and saves a 65536 byte file to your working directory/drawer/folder as sinewave.raw.

Use an oscilloscope to check the waveform generated...

It is entirely Public Domain and you may do with it as you please...

Enjoy finding simple solutions to often very difficult problems... ;o)

Bazza, G0LCU...

A Shell, Binary To Hexadecimal To Decimal Demo... (Bash)

2013-01-11T18:31:03-08:00

Bash recipe 578413 by Barry Walker (apple, bash, binary, decimal, demo, hexadecimal, linux, macbook_pro, shell, terminal).

This little DEMO may be common knowledge to the big guns but not to amateurs like myself, so......

This is an Apple Macbbok Shell/Terminal DEMO shell script to show how to:-

1) Create a binary file... 2) Save it to your DEFAULT /directory/drwawer/folder/... 3) Display a hexadecimal dump of said binary file to prove that it is binary... 4) Select a single BYTE of that file and save it as an ASCII text decimal _number_, also to your DEFAULT /directory/drawer/folder/... 5) Read this ASCII text decimal number back in again... 6) Add this string representation to a number... 7) Stop...

It was intended purely for OSX 10.7.5 and above using the default terminal and shell...

It does work on many Linux flavours and shells/terminals also however.

Written so the anyone can understand what is going on.

The two files generated and saved in this DEMO to your DEFAULT /directory/drawer/folder/ are:-

BinaryString.dat BinaryString.txt

This WILL lead to something very unusual in the not too distant future...

This is Public Domain and you may do with it as you wish...

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

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 Prompt Rainbow Color Chart (Bash)

2011-10-02T21:39:21-07:00

Bash recipe 577889 by userend (bash, color, prompt, ps1, rainbow, shell, terminal).

This is a simple loop that displays a rainbow of different colors.

Line-oriented processing in Python from command line (like AWK) (Python)

2011-04-14T19:49:16-07:00

Python recipe 577656 by Artur Siekielski (awk, bash, python, shell).

A very simple but powerful shell script which enables writing ad-hoc Python scripts for processing line-oriented input. It executes the following code template:

$INIT
for line in sys.stdin:
    $LOOP
$END

where $INIT, $LOOP and $END code blocks are given from command line. If only one argument is given, then $INIT and $END are empty. If two arguments are given, $END is empty.

Examples (script is saved as 'pyk' in the $PATH):

"wc -l" replacement: $ cat file | pyk 'c=0' 'c+=1' 'print c'
grep replacement: $ cat file | pyk 'import re' 'if re.search("\d+", line): print line'
adding all numbers: $ seq 1 10 | pyk 's=0' 's+=int(line)' 'print s'
prepending lines with it's length: $ cat file | pyk 'print len(line), line'
longest file name: $ ls -1 | pyk 'longest=""' 'if len(line) > len(longest): longest=line' 'print longest'
number of unique words in a document: $ pyk 'words=[]' 'words.extend(line.split())' 'print "All words: {}, unique: {}".format(len(words), len(set(words))'

Arduino Diecimila Board Access Inside A Linux Bash Shell. (Text)

2011-03-30T18:08:11-07:00

Text recipe 577627 by Barry Walker (access, arduino, bash, linux, shell, text).

The "code" in this recipe is a step by step "root" shell command line procedure for testing whether a(n) USB Arduino Dev Board is working or not. To get more recognisable characters displayed it is best to use a potentiometer wired as one end to +5V, the other end to Gnd and thw wiper to ANALOG IN 0. This has been tested on various Linux Distros and kept as simple as possible so that anyone can understand it.

The required ?.pde file for the Arduino Board can be found here:-

http://code.activestate.com/recipes/577625-arduino-diecimila-board-access-inside-winuae-demo/?in=lang-python

It is issued entirely as Public Domain by B.Walker, G0LCU, 30-03-2011, and you may do with it as you please.

Similar assumptions are made as in the URL above.

Enjoy finding simple solutions to often very difficult problems... ;o)