Bash script: Using "script" command from a bash script for logging a session

Question

I am trying to use script command for logging a bash session.

The script command is executed from withing a bash script but as soon as it is executed, the bash script terminates.

I have tried to invoke the command using various combination always with the same result (termination of the bash script as soon as the command is called). The output that I get is the following:

Script started, file is typescript root@ubuntu: ... 

I have also tried to invoke the command with an & in the end but again with no luck.

Can anyone tell me how should I invoke the command from a bash script?

Thanks

Answer 1

Your shell script did not terminate. It is still running. You are getting a prompt because script is spawning a new shell. the prompt you see is the prompt from the spawned shell.

The normal use case for script is something like this:

1. start script. this spawns a new shell.
2. do commands in the new shell.
3. exit the shell and drop to previous shell
4. examine the logfile created by script

So basically script is working as expected. You will have to find another way to achieve what you want.

You can log the execution of your script like this:

#! /bin/bash exec > logfile 2>&1 set -x FOO=BAR echo $FOO 

Explanation:

• exec > logfile 2>&1 redirects stdout and stderr to logfile
• set -x makes bash print every command before executing it

Example:

$ ./foo.sh   # (no output here because everything goes to logfile) $ cat logfile  + FOO=BAR + echo BAR BAR 

Disadvantage of this method is that the script prints no output for humans to see. Everything goes to the logfile.

Alternatively you can do it like this:

#! /bin/bash # nothing special here FOO=BAR echo $FOO 

Then execute like this:

$ script -c "bash -x foo.sh" Script started, file is typescript + FOO=BAR + echo BAR BAR Script done, file is typescript 

now output is directly visible and also saved to logfile (default name of logfile is typescript)

$ cat typescript  Script started on Mi 18 Mai 2011 01:05:29 CEST + FOO=BAR + echo BAR BAR  Script done on Mi 18 Mai 2011 01:05:29 CEST 

Answer 2

Your bash script is still running, but it has spawned a new interactive shell. The bash script is waiting for script to complete, which will only happen when the interactive shell is terminated (either by being killed, or by the user typing exit).

To make the command after script be logged by script, do it like this:

script build_log -c 'echo -e "* This line should appear inside the /"build_log/" log file..."' 

However, script will stop running after running that command.

To run multiple commands inside script, put those commands inside another bash script and specify that bash script as the command to run to the -c option.