I have a shell script that runs all the time looking for a certain type of file and then it processes the file through a series of other scripts. The script is watching a directory that has files uploaded to it via SFTP. It already checks the size of the file to make sure that it is not still uploading before it starts processing. I would like to place another check in the script that looks for the existance of another file before processing begins. The script looks like:

#!/bin/ksh
PATH=/gers/nurev/menu/pub/sbin:/gers/nurev/menu/pub/bin:/gers/nurev/menu/pub/mac
:/gers/nurev/menu/adm/sbin:/gers/nurev/menu/adm/bin:/gers/nurev/menu/adm/mac:/ge
rs/nurev/custom:/gers/nurev/fix:/gers/nurev/src_rev/fix:/gers/nurev/opt/path:/ge
rs/nurev/bin:/g/bin:/usr/bin:/etc:/usr/sbin:/usr/ucb:/sbin:.
ORACLE_HOME=/gers/nurev
ORACLE_SID=nurev
export PATH
export ORACLE_HOME
export ORACLE_SID
 
#
# Function : is_file_arrived file
# Arg(s)   : file = file to verify
# Output   : None
# Status   : 0 = yes file arrived, 1 = no
# Env.     : IFA_WAIT : interval (secs) for file size check (def=5)
#
 
is_file_arrived() {
   [ -z "$1" ] && return 1
   local file=$1
   local arrived=1
   local size1 size2
   if [ -f "$file" -a -z "$(fuser $file 2> /dev/null)" ] ; then
      size1=$(ls -l $file 2>/dev/null | awk '{print $5}')
      sleep ${IFA_WAIT:-15}
      size2=$(ls -l $file 2>/dev/null | awk '{print $5}')
      [ ${size1:-1} -eq ${size2:-2} ] && arrived=0
   fi
   return $arrived
}
 
 
processFile ()
{
   local fileName=$1
   local fileExtension=$2
   local fileNewName="/gers/nurev/datafiles/str${fileExtension}.asc"
   local filePrintPath="/gers/nurev/print"
   local fileTmpPath="/gers/nurev/tmp"
   local fileODIName="str${fileExtension}.pos"
   mv -Eignore $fileName $fileNewName     
   prepup $fileNewName $fileExtension
   mv -Eignore  $filePrintPath/$fileODIName $fileTmpPath/$fileODIName
   save2tmp $fileExtension
   call_siu $fileExtension
}
 
# Main Processing
 
nsec=1
while [[ "$(date +%H%M)" -lt 2329 ]]
do
   for fileName in /gers/nurev/datafiles/[Uu][Pp][Ll][Oo][Aa][Dd].[0-9][0-9][0-9
][0-9]
   do
      fileExtension=${fileName#*.}
      is_file_arrived "$fileName" && nsec=1 && processFile $fileName $fileExtension
   done
   sleep $nsec
   case $nsec in
      1)   nsec=15;;
      15)  nsec=45;;
      45)  nsec=90;;
      90)  nsec=300;;
      300) nsec=600;;
      600) nsec=900;;
      *)   nsec=1800;;
   esac
done

You can do something like this:

   for fileName in /gers/nurev/datafiles/[Uu][Pp][Ll][Oo][Aa][Dd].[0-9][0-9][0-9
][0-9]
   do
      fileExtension=${fileName#*.}
      [[ -a /gers/genret/tmp/poll_$fileExtension.txt  ]] && continue
      is_file_arrived "$fileName" && nsec=1 &&       processFile $fileName $fileExtension
   done

Forgive my ignorance, so how would bracketing the "-a" work?

[[ -a /gers/genret/tmp/poll_$fileExtension.txt  ]] && continue

The following code is equivalent :

if [[ -a /gers/genret/tmp/poll_$fileExtension.txt  ]]
then
   continue
fi