Is there an easy way to log all activity that a shell script does?

Question

Is there an easy way to log all activity that occurs from a shell script to a file?

I have a script. It outputs things like echo "instructions", as well as other program output. I know the commands:

command | tee -a "$log_file"

and

command >> logifle.log

What I'm asking is whether there is a shell parameter for logging, or a set command I can use or something like that. I don't necessarily want to add dozens of redirects or tee to files if I don't have to. I still want to get std output though - I just also want it to be logged.:wq

Solution 1

if you normally run your script with foo.sh, try running it (assuming it's a bash script) with bash -x foo.sh. If you want everything redirected to file, try bash -x foo.sh > file.log 2>&1 (note I'm redirecting stderr as well, remove the 2>&1 if you don't want this). If you also want to see what's going on, bash -x foo.sh 2>&1 | tee file.log.

Solution 2

There is a very easy and handy way:

Using script to make typescript of terminal session

1. Start the command script

   If the argument file is given, eg script ~/tmp/output, script saves the dialogue in this file. If no filename is given, the dialogue is saved in the file typescript

2. Start your script or what ever you want to start

3. If your script is finished, stop script via Ctrl-D

4. Check the output in the default output file typescript

---

To start your command in one step with script, use the parameter -c

-c COMMAND
    Run the COMMAND rather than an interactive 
    shell. This makes it easy for a script to capture
    the output of a program that behaves differently
    when its stdout is not a tty.

---

The usage of scriptinside your script makes no sense because script forks the shell or starts a new shell.

If the variable SHELL exists, the shell forked by script will be that shell. If SHELL is not set, the Bourne shell is assumed. (Most shells set this variable automatically).

Comments

[Admin]

LOL, :wq like I were in vim'

[Admin]

it boggles my mind that most people seem to do that instead of :x

[A.B.]

@Fabby I like my answer, but I don't see the little gray thing ;)

[goo]

I use script logfilename, so I get to pick it.

[j0h]

can I call "script" from my shell program?

[A.B.]

This makes no sense, see my improved answer.

[j0h]

I would like to run the command from inside the script , I will look into script this evening.

[sudodus]

+1. Thanks for this answer :-) script is useful also a monitoring via a fifo. From man script: "-f, --flush Flush output after each write. This is nice for telecooperation: one person does mkfifo foo; script -f foo, and another can supervise real-time what is being done using cat foo". It can also be used to monitor when a program is waiting for input or done for example by monitoring the timestamp of the fifo.