Bash - How to execute a script which is output from a different script

Question

I have a CLI which generates a bash script. How can I evaluate it immediatly without redirecting to a .sh file?

example is to change the following:

~: toolWhichGeneratesScript > tmp.sh
~: chmod +x tmp.sh
~: ./tmp.sh

to something like:

~: toolWhichGeneratesScript | evaluate

Thanks all for the very FAST answers. Embarrassed that I didn't think of that! Whose answer should I except??? — Avba
– Avba, Commented Sep 15, 2016 at 17:38
I would accept the one suggested by @thatotherguy because it's the most flexible solution, unless your toolWhichGeneratesScript might create a very long script, in which case the other ones are safer. — user1934428
– user1934428, Commented Sep 16, 2016 at 6:12

that other guy · Accepted Answer · 2016-09-15 17:37:11Z

2

You can pass in commands to run with bash -c (or sh -c):

bash -c "$(toolWhichGeneratesScript)"

   -c        If the -c option is present, then  commands
             are read from the first non-option argument
             command_string.   If  there  are  arguments
             after the command_string, they are assigned
             to the positional parameters, starting with
             $0.

Unlike piping to the shell, this leaves stdin free for you to interact with prompts and programs the script runs.

answered Sep 15, 2016 at 17:37

that other guy

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Comments

chepner · Accepted Answer · 2016-09-15 17:37:20Z

1

The shell reads its script from standard input:

toolWhichGeneratesScript | sh

(In fact, an interactive shell does the same; it's standard input just happens to be a terminal.)

Note that you need to know which shell to use; if your tool outputs bash extensions, then you have to pipe it to bash. Also, if the generated script itself needs to read from standard input, you have a bit of a problem.

answered Sep 15, 2016 at 17:37

chepner

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Comments

manzerbredes · Accepted Answer · 2016-09-15 17:37:39Z

0

Try to do this : toolWhichGeneratesScript | bash

answered Sep 15, 2016 at 17:37

manzerbredes

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