Shell Programming and Scripting

Hi all, I am trying to modify a script for research purposes and am having difficulty here as I have little prior experience with C-shell scripting.


The script looks as follows (it includes tcl commands like runFEP that you can ignore)

Code:

#!/bin/bash

for ((old=1, new=2; old<=4;  old++,new++))
a1=${old}%50
a2=${new}%50
do

cat > input${new}.conf <<EOF
${a1}

.
.
.
.
.
.
.
runFEP ${a1} ${a2} 0.02 \$nSteps ; # 50 windows outward


EOF

done

My question: I keep getting a syntax error when defining my two variables a1 and a2. I essentially need these variables to be
a1 = value of variable old divided by 50
a2 = value of variable new divided by 50


Any help here would be most appreciated!
Thanks

http://www.grymoire.com/Unix/CshTop10.txt

You mentionned C-Shell but your script start with

Code:

#!/bin/bash

Which is Bourn Again SHell : is it a modification that you did or is it from original file ?

a1=`expr ${old} / 50`

Thanks,
but I keep getting the same error

template_inp.sh: line 4: syntax error near unexpected token `a1='expr${old}/50''
template_inp.sh: line 4: `a1='expr${old}/50''

make sure you use ` instead of ' or "

Hi,
Seeing your error, seems you have not put a space between expr and ${old}. Use below command.
a1=`expr $old / 50`