Spawn command not found

1. that is an expect script, so ".exp" would be an appropriate file extension: mv bash.sh sftp.exp
2. do not launch it like bash bash.sh or sh bash.sh. Do this:
   1. make the program executable: chmod a+x sftp.exp
   2. launch it with ./sftp.exp or /path/to/sftp.exp or move it to a directory in your $PATH and launch it just with sftp.exp
3. after you send "myPassword" you have to "hit enter": send "myPassword\r"
4. while developing an expect program, add exp_internal 1 to the top.

Good luck, and come back with further questions.

It works OK for me (error from sftp: ssh: Could not resolve hostname XXX.XXX.XXX.XXX: Name or service not known), though the .sh extension for an expect (tcl) script is a little off-putting ;-)

Often when this sort of unexplainable/unpredictable behavior happens, it is because the script was edited under windows (notepad.exe), which uses \r\n to delimit lines. This plays havoc with unix/linux scripts, as only \n is expected as a line delimiter.

You can use the dos2unix and unix2dos utilities to convert between the two formats. As an experiment, I converted your script to "dos" format, and sure enough got a similar error:

ubuntu@ubuntu:~$ unix2dos bash.sh unix2dos: converting file bash.sh to DOS format ...ubuntu@ubuntu:~$ ./bash.sh ": no such file or directoryubuntu@ubuntu:~$ dos2unix bash.sh dos2unix: converting file bash.sh to Unix format ...ubuntu@ubuntu:~$ ./bash.sh spawn sftp -o IdentityFile=MyFile.ppk 500200243@XXX.XXX.XXX.XXXssh: Could not resolve hostname XXX.XXX.XXX.XXX: Name or service not knownCouldn't read packet: Connection reset by peersend: spawn id exp6 not open    while executing"send "myPassword""    (file "./bash.sh" line 4)ubuntu@ubuntu:~$ 

It seems /usr/bin/expect haven't been installed in your machine. So you will get 'command not found'

Use which expect to check, and install it to correct path.