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Re: TRICKY TASK USING AWK [message #92772 is a reply to message #92769]

Fri, 26 February 2016 04:03

dg86
Messages: 118
Registered: September 2012

Senior Member

On Friday, February 26, 2016 at 4:20:20 AM UTC-5, Sapna Mishra wrote:
> Hello all,
>
> What I have is:
>
> IDL> i=1
> IDL> $ awk -v var="$i" '{print $var}' tmp1.dat> tmp3.dat
>
> Upto this it is working ok. now what I want:
>
> IDL> fname[i]='QB0332_CHIP1_GRIS_600V_SCIENCE_SKY_SPECTRUM_FORS1. 2007_11_11T06_43_02.032redwave.dat'
> IDL> $ awk -v var="$i" '{print $var}' fname[i]> fnameout[i]
>
> Can I do it some how??? I found it most tricky. Basically can we use variables defined inside idl into shell commands.
>
> Anyone know how to solve this tricky job???

Without delving too deeply into the details of your specific application, it sounds like
you want to build up a string containing the desired command, and then to use SPAWN to
execute that command. The general idea is

IDL> cmd = 'awk my_awk_command ' + fname[i] + ' > ' + fnameout[i]
IDL> spawn, cmd

Note that you'll have to be careful about the quotation marks in the IDL string
that I've called 'cmd'. To get this right, you'll have to read the documentation on
IDL strings, specifically how to escape special characters (such as quotation marks).

You can double-check that you've built up the command properly by printing the string:

IDL> print, cmd

This should print exactly the command that you'd like to execute.

Finally, you'll have to be careful to insert spaces between the substrings that make up
your command so that the result is syntactically correct for execution by the shell.
In my sketched solution, I've deliberately placed a space after the placeholder
pseudocode 'my_awk_command'.

All the best,

David

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[Message index]

		TRICKY TASK USING AWK By: Sapna Mishra on Fri, 26 February 2016 01:20
		Re: TRICKY TASK USING AWK By: dg86 on Fri, 26 February 2016 04:03
		Re: TRICKY TASK USING AWK By: Sapna Mishra on Fri, 26 February 2016 06:55
		Re: TRICKY TASK USING AWK By: Mats Löfdahl on Fri, 26 February 2016 07:09
		Re: TRICKY TASK USING AWK By: Sapna Mishra on Mon, 29 February 2016 07:57
		Re: TRICKY TASK USING AWK By: Paul Van Delst[1] on Mon, 29 February 2016 08:07
		Re: TRICKY TASK USING AWK By: Heinz Stege on Mon, 29 February 2016 09:33
		Re: TRICKY TASK USING AWK By: Sapna Mishra on Mon, 29 February 2016 08:58
		Re: TRICKY TASK USING AWK By: wlandsman on Mon, 29 February 2016 09:44
		Re: TRICKY TASK USING AWK By: Sapna Mishra on Mon, 29 February 2016 22:08
		Re: TRICKY TASK USING AWK By: wlandsman on Tue, 01 March 2016 07:39
		Re: TRICKY TASK USING AWK By: wlandsman on Tue, 01 March 2016 19:36
		Re: TRICKY TASK USING AWK By: Sapna Mishra on Mon, 29 February 2016 22:12
		Re: TRICKY TASK USING AWK By: Mats Löfdahl on Tue, 01 March 2016 01:37
		Re: TRICKY TASK USING AWK By: Mats Löfdahl on Tue, 01 March 2016 01:50

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