dynamic editing using shell script

habzone2007 · #1 (**permalink**) 05-14-2008

Hi,

I would like to edit an input data-file by changing a variable in it
in steps:

For ex: If my input file is 'big.in', then it has the following data:

2.54 0.01 0.5 0.0

My source code then reads this above line, executes and gives out some
output. Then ,
I want to increment the value "0.01" in the above file by some step
and the source code reads it again, executes and gives another output
and so on...

I can use Finding & replacing (ex: 's/0.01/0.02/g') to replace a
previous value, but if there are 100 values I need to substitute, it
becomes cumbersome..there must be a better way, like using a variable
for finding and replacing...

Any help would be appreciated

Thanks

Smiling Dragon · #2 (**permalink**) 05-14-2008

I think you are being a bit vague here as to how much you want to add and to which values, but I'd guess at something like this:

Code:

#!/bin/sh
INC=0.01
while read line
do
  lineout=""
  for num in $line
  do
    num=expr $num + $INC
    if [ -z "$lineout" ]
    then
      lineout=$num
    else
      lineout="$lineout $num"
    fi
  done
  echo "$lineout"
done

(Untested)

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