what does this piece of code do? Post: 302075599

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Top Forums Shell Programming and Scripting what does this piece of code do? Post 302075599 by Vikas Sood on Monday 5th of June 2006 03:59:27 PM

06-05-2006

Registered User

what does this piece of code do?

Hi All,

I am trying to understand and change some code written by some programmer a while ago. There are following three lines of code that I am unable to grasp. Could anybody please help me understand it?

1) cd - > /dev/null

2) fname=`basename "$1"` where $1 = /dirA/dirB/a.txt
dname="${1%/$fname}"

I understand in this case fname would give me a.txt but what will dname be? I tried to echo dname on command line but it comes out to be blank

3) var1=/xx/yy
var2=${var1##*/}1

The result of the above is yy1. How does var2 get set to yy1?

4) inUse=`fuser "$1" 2>&1`
outputLines=`cat <<! | wc -l
${inUse}
!`

What I dont understand in above code is, if the intent of the programmer is just to count the number of rows returned by inUse variable, why did she choose to have <<! ?? Is there a good reason behind it or is just too complex without any good reason?

Thanks guyz.

Last edited by Vikas Sood; 06-05-2006 at 05:07 PM..

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mcxalter

mcxalter(1)							  USER COMMANDS 						       mcxalter(1)

  NAME
      mcxalter - various network transformations

  SYNOPSIS
      mcxalter [-imx <fname> (specify matrix input)] [-abc <fname> (specify label input)] [-tab <fname> (use tab file)] [-o <fname> (output)] [-tf
      spec (apply tf-spec to input matrix)]

  DESCRIPTION
      This utility supplies various transformations of networks.

  OPTIONS
      -abc <fname> (label input)
	The file name for input that is in label format.

      -imx <fname> (input matrix)
	The file name for input that is in mcl native matrix format.

      -tab <fname> (use tab file)
	This option causes the output to be printed with the labels found in the tab file.  With -abc this option will, additionally, construct  a
	graph  only on the labels found in the tab file.  If this option is used in conjunction with -imx the tab domain and the matrix domain are
	required to be identical.

      -tf <tf-spec> (transform input matrix values)
	Transform the input matrix values according to the syntax described in mcxio(5).

      -o fname (output file)
	Output file.

  AUTHOR
      Stijn van Dongen.

  SEE ALSO
      mcxio(5), mcx(1), mcxsubs(1), and mclfamily(7) for an overview of all the documentation and the utilities in the mcl family.

  mcxalter 12-068						      8 Mar 2012							 mcxalter(1)