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How can I get an expect script to read a password from a file so it can be used to pass it to a program that requires that password.

How can I get an expect script to read a password from a file so it can be used to pass it to a program that requires that password.
I currently used autoexpect to create expect scripts, but the passwords are then hard coded.
Note: My OS is Linux

here is a snippet from my expect script
send -s -- "cd \$ADMIN_SCRIPTS_HOME"
expect -exact "cd \$ADMIN_SCRIPTS_HOME"
sleep .1
send -s -- "\r"
expect -exact "applmgr@appsrvr:/u01/blah/SID/R122/fs1/inst/apps/SID_hostname/admin/scripts> "
sleep .1
send -s -- "adop phase=fs_clone"
expect -exact "adop phase=fs_clone"
sleep .1
send -s -- "\r"
expect -exact "Enter the APPS password:"
sleep .1
send -s -- "hard_coded_password\r"

I want to be able to read the APPS password from a file and use it in this expect script.

noci

How can I get an expect script to read a password from a file so it can be used to pass it to a program that requires that password.
I currently used autoexpect to create expect scripts, but the passwords are then hard coded.
Note: My OS is Linux

The OS is lightly relevant here, more important it establishes that you need a scripting language like perl, python, bash, ... and those are available.
So much more info is needed what program does need the password, how does it accept passwords for a start.
In some cases the program can support this or can accept the authentication info in different ways.

Due to lack of info the question is alike: "how do i do something".

Les Ostness

ASKER

noci, Good point. I have updated the question.

ASKER CERTIFIED SOLUTION

noci

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Les Ostness

ASKER

noci,

I like this a lot. I will test it. Thank you.

skullnobrains

Expect is bundled with tcl

You can use the regular open and read from tcl. I have a snippet available if needed. Unfortunately not on my mobile phone ;) but that should be trivial enough once you know you can use tcl

skullnobrains

From the top of my head

set fp [ open pathtofile r]
set password [ read fp ]

Obviously replace pathtofile adequately

Les Ostness

ASKER

I like both your solutions. I tested noci's and implemented that solution already. I'm sure skullnobrains solution would also work.
Thank you both.

skullnobrains

good to see you got it running

just in case you're interested, here is a snipet from an ugly but working piece of code
you can remove the '\\\' which are escapes for the shell

this also demonstrates ways to mix shell and expect scripts so shell commands can be interleaved directly : "set password [ $(cat PASSWORDFILE) ]" would work in the below case and similar stuff would work in other cases depending on the quoting in use. i prefer reading the file from within expect which reduces the password exposure.

also note that many command line tools can read passwords from files directly using command line parameters

        expect $DBG -c "`cat <<EOF
        set timeout 30
        log_user $LOG
        #log_file -noappend /dev/stderr
        
        # /!\ exit in the function
        proc readfile { file } {
                if [catch {set fp [open \\\$file r] } errmsg] {
                        send_error "failed to open file='\\\$file' : \\\$errmsg\n"
                        exit 1 
                }
                set ret ""
                while { [gets \\\$fp data] >= 0 } { set ret "\\\$ret\\\$data" }
                close \\\$fp
                return \\\$ret
        }
        
        set p [ string trim [ readfile "$passwordfile" ] ]
        set pen [ string trim [ readfile "$enpasswordfile" ] ]
        
        ...

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