Bash: Default variable with command substitution

Question

Is there any way to accomplish the following in one stroke using Bash?

my_var=${$(grep -E '^setting_1' /settings.conf):-default_setting1}

As opposed to:

my_var=$(grep -E '^setting_1' /settings.conf); my_var=${my_var:-default_setting}

choroba · Accepted Answer · 2016-02-11 16:44:05Z

up vote 0 down vote accepted

You can output the default if the grep fails:

var=$( grep -e '^setting_1' || echo default_setting )

Note that you didn't close the quotes (and without the file argument, grep will filter stdin).

answered Feb 11 at 16:44

choroba

15.9k12242

Thanks, I fixed the typos, it was kind of a thoughtless example for the sake of the question. – Gregg Leventhal Feb 11 at 17:18

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