Shell Programming and Scripting

fileone_yyyy_mm_dd.dat
filetwo_yyyy_mm_dd.dat
filethree_yyyy_mm_dd.dat

filecount=`ls dir1|grep -c "fileone"*`
if [ filecount -gt 0]; then
 echo "fileone ixists"
fi

# Today's date
DATE=$(date +%Y_%m_%d)

for X in fileone filetwo filethree
do
        [ -f "${X}_${DATE}.dat" ] && echo "${X} exists"
done

[ -f "${X}*.dat" ] && echo "${X} exists"

# Today's date
DATE=$(date +%Y_%m_%d)

for X in fileone filetwo filethree
do
        [ -f "${X}_${DATE}.dat" ] && echo "${X} exists"
done

YMD=$(date +%Y_%m_%d)
#
if [ -f "fileone_${YMD}.dat" -a -f "filetwo_${YMD}.dat" -a -f "filethree_${YMD}.dat" ]
then
        echo "All three files exist
else
        echo "One of more files is missing"
fi

filecount=$(ls -1d fileone_????_??_??.dat filetwo_????_??_??.dat filethree_????_??_??.dat 2>/dev/null | wc -l)
if [ $filecount -ne 3 ]
then
        echo "one or more of the three files is missing"
fi