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I have a bash script that calls various commands and prints some output (both from the called commands themselves, such as git pull, and informative messages generated by the script itself such as Operation took XX minutes.

I'd like to capture the whole output to a file from the script itself: basically I'm trying to avoid the need to call ./myscript.sh | tee file.txt for non-relevant-here reasons.

Basically I'd like to do something like this:

startCapture

git pull

echo "Text"

other-command

endCapture

I also require the output to be printed on my shell while the script is running.

The final goal is to:

  1. run ./myscript.sh without additional shell constructs
  2. see the output on the terminal as I do now
  3. obtain a file on disk with the whole output

Is this even possible?

Dan Dascalescu
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Dr. Gianluigi Zane Zanettini
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    For those that end up here from Google, you might also consider this answer (https://unix.stackexchange.com/a/164017/103505) to just put all the code you want to output in a function in the script and then redirect the output of that function. – cjbarth Apr 15 '20 at 13:22

3 Answers3

8

You can always invoke script inside a script to log everything.

As to print and log everything at the same time in a bash script to log.txt:

#!/bin/bash

if [ -z "$SCRIPT" ]
then 
    /usr/bin/script log.txt /bin/bash -c "$0 $*"
    exit 0
fi

echo teste

Seeing the log log.txt:

$ ./a.sh
Script started, output file is log.txt
teste

Script done, output file is log.txt
$ cat log.txt
Script started on Fri Feb 16 17:57:26 2018
command: /bin/bash -c ./a.sh 
teste

Script done on Fri Feb 16 17:57:26 2018
Rui F Ribeiro
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    If I understand correctly (some explanations would help :), the script is trying to detect if it's running under script, and not re-execute itself. As of Ubuntu 20, it looks like $SCRIPT is not set, so the script goes into an infinite loop. – Dan Dascalescu Jun 01 '20 at 10:06
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    Good idea to use script though, because it allows for interactive terminal output, e.g. Carriage Return, to work. In effect, commands that display single-line progress output (archivers for example), behave normally. As for solving the infinite loop problem, we can test the shell level: if (( $SHLVL < 3 )); then script...; fi. – Dan Dascalescu Jun 01 '20 at 10:35
  • Also, the arguments of the scripts end up being concatenated and passed in the code argument to the shell started by script (not /bin/bash, that /bin/bash argument is ignored with util-linux script) – Stéphane Chazelas Jul 24 '20 at 08:52
2

A method I found to capture all output from any session is to start a new bash session and tee to a log file. its really useful for tracking more then just a script.

bash | tee ~/bash.log #this will save standard output until the bash session is ended
bash 2>&1 | tee ~/bash.log #this will save all output including errors until the bash session is ended

or you can just tee the script it's self

./myscript.sh | tee ./myscript.log #this will log only the output of the script.

thebtm
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  • Your solution addresses STDOUT, but not STDERR – user1404316 Feb 16 '18 at 17:28
  • I put in an example with 2>&1 – thebtm Feb 16 '18 at 17:31
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    I don't think this answers the question because requirement #1 was "run ./myscript.sh without additional shell constructs". – Dan Dascalescu Jun 01 '20 at 09:36
  • This question was edited 6 hours ago, I didn't have that information when I first answered the question. It was using > output instead of tee and that is why I shared the option for tee. – thebtm Jun 01 '20 at 16:04
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    @thebtm your answer is wrong. 2>&1 is on the wrong side of the command, it should be on the left hand of the pipe because you want to capture "the error output of the script" not "the error output of the tee command" – vdegenne Dec 08 '22 at 21:03
  • @vdegenne corrected the answer to be a better answer. Thank You – thebtm Dec 13 '22 at 16:42
2

You want to use tee.

Ex:

echo "Hello World" | tee out.txt

This creates a file out.txt with the output from the command and prints it to the screen. Use "tee -a filename" if you want to append to the file.

echo "Hello" | tee -a out.txt
echo "World" | tee -a out.txt

out.txt will have two lines Hello and World (without -a it would only have world)

If you want to save the entire script and output the entire script: 

./script.sh | tee output.txt
Mark
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    Your solution addresses STDOUT, but not STDERR – user1404316 Feb 16 '18 at 17:26
  • https://unix.stackexchange.com/a/61932/268823 explains how to do STDOUT and STDERR – Mark Feb 17 '18 at 21:17
  • I don't think this answers the question because requirement #1 was "run ./myscript.sh without additional shell constructs". – Dan Dascalescu Jun 01 '20 at 09:36
  • I guess one way to do it would be to put everything into a function, and use tee at the end. That would effectively work as a start and stop capture. And redirecting the STDERR if that is the intention. – Mark Jul 06 '20 at 17:01