Hello, I had written a shell script that accepts input file as cmd line argument and process this file. Code: if [ $# -eq 1 ]; then if [ -f $1 ]; then . $1 LOGFILE="$LOG_FILE/MIG_BIOS.log"; get_input_file else ERROR_CODE=MSCRM0005_003 error "$ERROR_CODE : Input file $1 is not available"; exit 1 fi else echo "usage : $usage"; fi I want a help in writting a get_input_file function which checks for file name format. My input file name format is MIG_CR_<TYPE>_<TIMESTAMP>.<EXT> Code: get_input_file() { FILE = '$1' #checking file exist or not if [ ! -f $FILE ]; then echo "$FILE : does not exists" exit 1 elif [ ! -r $FILE ]; then echo "$FILE: can not read" exit 2 fi // TO do // check file name format is correct or not } Can anyone tell me how can I check the format of file name? Please help me out. Thanks in advance.