How do I log output of a shell script and also display on the screen?

Question

I am running a script called upgrade.sh

ANd upgrade.sh calls a script called roll.sh

roll.sh >> logfile.text

But roll.sh has some questions and prompts, and the redirect is preventing those outputs from hitting the screen. I cannot edit roll.sh.

I also tried `results=$(roll.sh)

Even then, the output was not coming onto the screen

score 15 · Accepted Answer · answered Feb 15 '13 at 18:49

15

Use tee, it was created specifically for this purpose: to forward standard input to the screen and one or more files. Make sure to use the -a option to append to logfile.text if you don't want to overwrite it.

roll.sh | tee -a logfile.text

answered Feb 15 '13 at 18:49

Cory Klein

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The only thing that I would add is that you should probably do ```roll.sh 2>&1 | tee -a logfile.txt``` to also capture error output – Srdjan Grubor Feb 17 '13 at 19:18

score 1 · Answer 2 · answered Feb 15 '13 at 18:50

1

You want tee:

TEE(1)                           User Commands                          TEE(1)



NAME
       tee - read from standard input and write to standard output and files

answered Feb 15 '13 at 18:50

evil otto

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score 1 · Answer 3 · answered Feb 15 '13 at 18:54

1

A common way to handle that is to have the script write its prompts to stderr instead of stdout.

answered Feb 15 '13 at 18:54

William Pursell

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True, but he said he can't modify `roll.sh` – chepner Feb 15 '13 at 18:59

How do I log output of a shell script and also display on the screen?

3 Answers3