hello i am new to scripting and Linux in general. i am going to school for sys admin and i will need at least some knowledge on scripting. i have been so far ok with learning basic scripting now i am stuck. with a assignment that i was given it was create a script that will tell you if a number is odd or even, i got it to work but don't know why. the script is this:
Code:
#!/bin/bash
echo "please tell me a number between 0 and 20"
read num
even=$(( $num % 2 ))
if [ $even -eq 0 ]
then echo "you have a even number"
else echo "you have a odd number"
fi
my question is what does this command do
Code:
even=$(( $num % 2 ))
does it take the number and break it down to the lowest denominator (0 or 1) or does it do something else.
also what doe the % mean in scripting. i looked it up and found out its called that modulo (remainder) but i do not know what that means.
I am not trying to get an easy grade but rather i am trying to learn this because i have intro to programming next quarter and if I learn this now it will help me in the future.
one final thing. if anyone could tell me of a good beginner bash script "cheat sheet" so i can understand the scripting commands. i saw the Unix commands tab but i did not know which one to pick.
thank you
Last edited by Don Cragun; 05-11-2015 at 08:27 PM..
Reason: Add CODE and ICODE tags.
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Discussion started by: arun888
17 Replies
LEARN ABOUT DEBIAN
liquidsoap
LIQUIDSOAP(1) General Commands Manual LIQUIDSOAP(1)NAME
liquidsoap - a multimedia streaming language
SYNOPSIS
liquidsoap [options] [script|expression]
DESCRIPTION
Liquidsoap is a programming language for describing multimedia streaming systems. It is very flexible, making simple things simple but
giving a lot of control for advanced uses. Liquidsoap supports audio, video and MIDI streams, and a wide range of input/output operators
including Icecast and various soundcard APIs. It can perform a broad range of signal processing, combine streams in various ways, support
custom transitions, generate sound procedurally... and all this can be assembled as you wish. Input files can be accessed remotely, or
even be synthesized on the fly using external scripts such as speech synthesis. Finally, interaction with a running liquidsoap instance is
possible via telnet or socket.
Liquidsoap scripts passed on the command line will be evaluated: they shall be used to define the streaming system to be ran. It is possi-
ble to pass multiple scripts; they will all be ran successively, and definitions from one script can be used in subsequent ones. A script
will be read from standard input if - is given as script filename. Information about scripting liquidsoap is available on our website:
http://savonet.sf.net/
If the parameter is not a file it will be treated as an expression which will be executed. It is a convenient way to test simple one-line
scripts. When running only one-liners, the default is to log messages directly on stdout rather than to a file.
OPTIONS -
Read script from standard input.
-- Stop parsing the command-line and pass subsequent items to the script.
--debug
Print debugging log messages.
--dynamic-plugins-dir path
Directory where to look for plugins.
--errors-as-warnings
Issue warnings instead of fatal errors for unused variables and ignored expressions. If you are not sure about it, it is better to
not use it.
--interactive
Start an interactive interpreter.
--list-plugins
List all plugins (builtin scripting values, supported formats and protocols).
--list-plugins-xml
List all plugins (builtin scripting values, supported formats and protocols), output as XML.
--no-pervasives
Do not load pervasive script libraries.
--version
Display liquidsoap's version.
-c, --check
Check and evaluate scripts but do not perform any streaming.
-cl, --check-lib
Like --check but treats all scripts and expressions as libraries, so that unused toplevel variables are not reported.
-d, --daemon
Run in daemon mode.
-f, --force-start
For advanced dynamic uses: force liquidsoap to start even when no active source is initially defined.
-h plugin
Print the description of a plugin, eg. a builtin scripting function.
-i Display infered types.
-p, --parse-only
Parse scripts but do not type-check and run them.
-q, --quiet
Do not print log messages on standard output.
-r filename
Process a request.
-T, --disable-telnet
Disable the telnet server.
-U, --disable-unix-socket
Disable the unix socket.
-t, --enable-telnet
Enable the telnet server.
-u, --enable-unix-socket
Enable the unix socket.
-v, --verbose
Print log messages on standard output.
--conf-descr-key key
Describe a configuration key.
--conf-descr
Show all configuration keys with their documentation.
--conf-descr-liqi
Show all configuration keys with their documentation in liqi (documentation wiki) format.
--conf-dump
Dump the configuration state
-help, --help
Display this list of options
SEE ALSO
Our website http://savonet.sf.net/ and the HTML documentation coming with your distribution of liquidsoap.
AUTHOR
Savonet team <savonet-users@lists.sourceforge.net>
Liquidsoap 1.0.1 June 25, 2012 LIQUIDSOAP(1)