using expect to switch users in a script

[esolve]

hi, I need to switch users in a script
I'm newbee to expect
I wrote two files

1 sudo.exp, since su4098 is used as root in my laptop

#!/usr/bin/expect
spawn su su4098
expect *Password:*
send mypsw\n
interact

2 test.sh

ls
./sudo.exp
tcpdump -i wlan0
su esolve
ls

however, in test.sh
when it switches to su4098,namely the root
it stops a while
and tens of seconds later, it run the password as a command
and the following commands: tcpdump, su esolve, and ls are not run

what is wrong with my scripts?

besides, how to share variables between users in a script?
thanks？

[atreyu]

hi, I need to switch users in a script
I'm newbee to expect
I wrote two files

1 sudo.exp, since su4098 is used as root in my laptop

#!/usr/bin/expect
spawn su su4098
expect *Password:*
send mypsw\n
interact

2 test.sh

ls
./sudo.exp
tcpdump -i wlan0
su esolve
ls

however, in test.sh
when it switches to su4098,namely the root
it stops a while
and tens of seconds later, it run the password as a command
and the following commands: tcpdump, su esolve, and ls are not run

why not just pass the tcpdump command as a command directly to su in your expect script? e.g.:

#!/usr/bin/expect
spawn su su4098 -c "tcpdump -i wlan0"
expect *Password:*
send mypsw\n
interact

[esolve]

I need to use some variables with tcpdump
these variables will be lost in the sudo.exp

why not just pass the tcpdump command as a command directly to su in your expect script? e.g.:

#!/usr/bin/expect
spawn su su4098 -c "tcpdump -i wlan0"
expect *Password:*
send mypsw\n
interact

[atreyu]

I need to use some variables with tcpdump
these variables will be lost in the sudo.exp

could you be more specific about "variables will be lost"? If you mean the "-i wlan0", they are passed to tcpdump for me, provided that I enclose the whole command in double-quotes (as shown).