Shell Programming and Scripting

#!/bin/bash
DATE=`date +"%d-%m-%Y-%H:%M"`
FLAG=FIRST
stream=IUCS
path="/bigpfstest/DPI_INVESTIG/IUCS"
for  files in `printf "%s\n" $path/* | tail -5`
        do
	TTHEX=`awk -F ',' 'END{print $4}' $files`
        TIMESTAMP=$( date +'%H:%M:%S' -r $files)
        TRANS_TIME=$(date -d @$(expr `printf "%d" 0x$TTHEX` / 1000) | awk '{print $4}')
        TIME_LAG=$(date +%H:%M:%S -ud @$((`expr $(date -u -d "$TIMESTAMP" +"%s") - $(date -u -d "$TRANS_TIME" +"%s")`)))
        echo "${DATE} ${stream} ${FLAG} $(ls -l $files | awk '{print $9}'| cut -d '/' -f5) ${TIMESTAMP} ${TRANS_TIME} ${TIME_LAG}"  >>IUCS_TEST.csv
        done

while true
do
    for ...
    do
       ...
       exit 0
    done
    sleep 123
done

while [ ! -f $path/* ]
do
    sleep 5              # 5 second pause, or whatever else you want to do
done

# Rest of script here

until [ -f $path/* ]
do
    sleep 5              # 5 second pause, or whatever else you want to do
done

# Rest of script here