What does this script means?

$ARC_PROG -f $INP_DIR/$INP_FIL -a $ARC_DIR/$FIL_TYP/$COMP_CD/$FY_STAMP/$MD_STAMP

Everything is as alias or defined variable

Check for the actual source.

There should be some source which would have defined something like

ARC_PROG=/somedir/someprog
INP_DIR=/home/user/input_directory



If you could get the source of the script, we can try then !