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Full Discussion: Scripting Question (For Loop)
Top Forums UNIX for Dummies Questions & Answers Scripting Question (For Loop) Post 302953021 by neutronscott on Tuesday 25th of August 2015 01:36:49 AM
Old 08-25-2015
Quote:
Originally Posted by shah9250
However, what do you mean by properly split list of files?
See the following shell session example:

Code:
mute@tiny:~$ mkdir shah9250
mute@tiny:~$ cd shah9250/
mute@tiny:~/shah9250$ touch 'file with spaces'
mute@tiny:~/shah9250$ for f in $(ls); do echo "work on [$f]"; done
work on [file]
work on [with]
work on [spaces]
mute@tiny:~/shah9250$ for f in *; do echo "work on [$f]"; done
work on [file with spaces]

We know there is only one file and the loop should only be called once, but with that use of $(ls) it's not. Quoting and word splitting are the toughest parts of learning the shell, in my opinion. Once that clicks things are much easier.

Quote:
Originally Posted by shah9250
Also what is a glob? Also you used a wildcard (*) in the "for" statement, so how does the variable $file receive input?
Glob is filename expansion. * is a wildcard that matches anything. You can simply do echo * or echo *.txt to show all files or all files ending in .txt. My meaning wasn't to distract from the for loop, just for down the road you'll want to use best practices. Filenames can contain any character except the NUL character and the path delimiter / and a great deal of care must be taken to make robust scripts.

I cannot recommend Greg's wiki enough. The bash guide on the site is excellent value for the price: BashGuide - Greg's Wiki
This User Gave Thanks to neutronscott For This Post:
shah9250
 

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LEARN ABOUT NETBSD

cmpci

CMPCI(4)						   BSD Kernel Interfaces Manual 						  CMPCI(4)

NAME

     cmpci -- C-Media CMI8x38 audio device driver

SYNOPSIS

     cmpci* at pci? dev ? function ?
     audio* at audiobus?
     mpu*   at cmpci?
     opl*   at cmpci? flags 1

DESCRIPTION

     The cmpci device driver supports C-Media CMI8x38 based sound cards.

     The device has SPDIF input/output interfaces, 16bit CODEC with analog mixer, OPL3 FM Synthesizer, and MPU401 compatible MIDI I/O port inter-
     face.

MIXER DEVICE

     The mixer device of cmpci driver can be accessed via mixerctl(1) command.	The complex structure is analyzed as follows.

     SPDIF in  ----------------------
     #1(coax)->|spdin1		    |  R    -----------------------
     #2(opt)-->|spdin2	spdif.input |--*->--|spdin   spdif.output |--> SPDIF
	    -->|spdout		    |  | -->|playback		  |    output
	    |  ----------------------  | |  -----------------------
	    --------------------<------+-*
	  ---------<-------------------+-+----------------------------------
	  |  ------------------------  | |   -----------------------	   |
	  -->|legacy  spdif.output. |--+-*-->|spdout		   |	   |
	  -->|wave    playback	    |  ----->|spdin  spdif.monitor |----   |
	  |  ------------------------	  NC-|off		   |   |   |
	  ---------<-- spdif		     -----------------------   |   |
	      -------+------- dac ------------	  -----------------    v   |
     wave  -->|playback.mode|---->|inputs.dac|-*->|inputs.dac.mute|->----- |
     playback ---------------	  ------------ R  -----------------  | + | |
		       -----------------     ---------------------   |mix| |
     FM synthesizer -->|inputs.fmsynth |--*->|inputs.fmsynth.mute|-->----- |
		       -----------------  R  ---------------------     *->--
     CD        ----------------------	---------------------------    v
     LINE-IN ->|inputs.{cd,line,aux}|-*>|inputs.{cd,line,aux}.mute|->-----
     AUX       ---------------------- R ---------------------------  |	 |
	       ------------------				     |	 |
     PC-SPK -->| inputs.speaker |----------------------------------->| + |
	       ------------------				     |	 |
	       -------------------  ------------  -----------------  |mix|
     MIC --*-->|inputs.mic.preamp|->|inputs.mic|->|inputs.mic.mute|->|	 |
	   |   -------------------  ------------  -----------------  -----
	   |   ------------   ----------------- 		      |
	   --->|record.mic|-->| 	      | 		      v
	       ------------   | record.source |-->to	     -----------
			 *R-->| (select, mix) |   recording  |outputs.*|-->
			      ----------------- 	     ----------- SPK
								      (front)

     Note the 2nd SPDIF input exists only on CMI8738/PCI-6ch versions.

MIXER EXAMPLES

     Here are examples about wave playback and SPDIF input/output ports.

     Playback to speaker, SPDIF input to SPDIF output
	      mixerctl -w playback.mode=dac spdif.output=spdin spdif.monitor=off

     Playback to SPDIF output, SPDIF input to speaker
	      mixerctl -w playback.mode=spdif spdif.output=playback spdif.output.playback=wave spdif.monitor=spdin

     SPDIF input to both SPDIF output and speaker
	      mixerctl -w spdif.output=spdin spdif.monitor=spdin

     Playback to both SPDIF output and speaker
	      mixerctl -w playback.mode=spdif spdif.output=playback spdif.output.playback=wave spdif.monitor=spdout

     Mix playback and SPDIF input to speaker
	      mixerctl -w playback.mode=dac spdif.monitor=spdin

SEE ALSO

     mixerctl(1), audio(4), midi(4), mpu(4), opl(4), pci(4)

HISTORY

     The cmpci device driver appeared in NetBSD 1.5.

BUGS

     4ch/6ch playback is not yet available.  Joystick port is not supported.

     spdif.output.playback=legacy does not seem to work properly.

BSD
								   June 22, 2005							       BSD
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