variable scope / loops?

[bentaylor]

hello, i'm trying to write a script to do an action on all, say, *.ext, files, but not if it's name is listed in a file called "excludelist".
so I have

for i in *.ext; do
{
 if [ -f $i ] ; then
  includefile=1
  if [ -f excludelist ]; then
    cat excludelist |while read line; do {
      if [ "${line}" == "$i" ]; then
        includefile=0
        break
      fi
    }; done
  fi
  if [ "$includefile" == "1" ] ; then
  #... (do my actions on file)
  fi
}; done

but unfortunately, when I set includefile=0, it appears to be creating its own variable of the same name in the scope of the inner loop - as the variable I create by setting includefile=1 before that loop starts isn't being modified!

How do I modify the existing variable from within the scope of the inner loop?

[bhaslinux]

use export
export includefile=0
will make it global to the script !

[drl]

Hi.

A pipeline causes new processes to be created, which will use new, different variables. One solution is to avoid pipelines. A short example:

#!/bin/sh

# @(#) s1       Demonstrate new scope for pipeline.

cat >t1 <<EOF
one
two
thr
EOF

echo
echo " Situation with piping into loop."
i=0
echo " Value of i before loop: $i"

cat t1 |
while read line
do
  i=$(( i+1 ))
  echo " Value of i inside loop: $i"
done

echo
echo " Value of i after loop: $i"

echo
echo " Situation with input re-direction:"
echo
i=0
echo " Value of i before loop: $i"
while read line
do
  i=$(( i+1 ))
  echo " Value of i inside loop: $i"
done < t1

echo
echo " Value of i after loop: $i"

exit 0

Which produces:

% ./s1

 Situation with piping into loop.
 Value of i before loop: 0
 Value of i inside loop: 1
 Value of i inside loop: 2
 Value of i inside loop: 3

 Value of i after loop: 0

 Situation with input re-direction:

 Value of i before loop: 0
 Value of i inside loop: 1
 Value of i inside loop: 2
 Value of i inside loop: 3

 Value of i after loop: 3

Best wishes ... cheers, drl

[bentaylor]

Hi.

A pipeline causes new processes to be created, which will use new, different variables. One solution is to avoid pipelines. A short example:
(working example)
Best wishes ... cheers, drl

that works perfect, cheers