Echo shell log while entering and then exit

Question

While I type a command, this command will authenticate with a remote server and do a bunch of things. If pass, it will give me a bash shell with its environment.

My goal is to save these log which prints out into my terminal for future inspection. Let's say my command called target.

While I type target, it throws the following msg.

Version:        V1.94
Options:
Date:           Thu Jun  6 17:18:39 2019
OS:             CentOS release 6.10 (Final)
....
[DEV]target>

Notice the last line implied I've entered the target shell environment.

I've tried echo $(target) > output.log, but it will be stuck until I type CTRL+C.

Environment: CentOS 6.10

Update

Let's say I want to make this script automatically run when I activate my machine. However, it will still be stuck while executing the target command because it entered a shell and didn't leave.

#!/bin/bash
script -c target output.log
FILENAMEME=output.log
aws s3 cp "$FILENAME" s3://logs/

Answer 1

You may want to try script:

script -c target output.log

This would start the command target and save a transcript of the whole session, until target terminates, into the file output.log. If the command (your target) is several words long, quote the full command.

See the manual for script (man script).

Answer 2

If you can't change the target command itself, then this should be helpful:

target | tee output.bak

output.bak will contain a copy of all the output (just stdout in this example), so you'll have to trim it if you want just the initial info.