Below are my two script codes:
**a.sh**

#!/bin/sh

SRC_PATH="/xx/xxxx"
HOST='ftp.xxx.xxx.com'
USER='xxxx'
PASS='xxx'
FTP_SRC_PATH='out'

**b.sh**
#!/bin/sh

/xx/xxx/a.sh

ftp -n $HOST <<END_SCRIPT
quote USER $USER
quote PASS $PASS
binary
prompt off
cd $FTP_SRC_PATH
lcd $SRC_PATH
mget IMS_*.ZIP
bye
END_SCRIPT