Shell Programming and Scripting

#! /bin/bash

pCheckForFile ()
{
fIn="/path/to/file/to/check.for"   # alternatively a filename could be provided as argument
# fIn="$1"                         # alternatively a filename could be provided as argument
chText="TRL"                       # text to check for
iRetVal=1                          # value/error status to return

if [ -f "$fIn" ] ; then
     if grep -q "$chText" "$fIn"
          iRetVal=0
     fi
fi

return iRetVal
}



# main()

while ! pCheckForFile ; do
# while ! pCheckForFile /some/file/to/check; do   # this is the alternative call
     sleep 180
done

doSomething

exit 0

#! /bin/bash

pCheckForFile ()
{
<same as above>
}



# main()

while : ; do
     # if pCheckForFile  /some/file/to/check ; then  # alternative, when a filename is provided as argument
     if pCheckForFile ; then
          doSomeThingHere
     fi
     sleep 180
done

exit 0