Shell – how to reference a variable in fish shell with a default fallback

fishshell

What is the fish shell equivalent to the following bash:

echo ${TEST:-1}

In bash this would print the value of TEST if there was one, or 1 if there was not.

Best Answer

I believe you need temponary variable (or a function). If $TEST doesn't exist, it's expanded to nothing, and $test_or only contains 1. It would be nice to have real way of doing that, but currently the syntax is issue, and it doesn't appear it's really needed for most purposes.

set test_or $TEST 1
echo $test_or[1]

Also, if all you want is to modify $TEST if it doesn't exist already, you can use set -q.

set -q TEST; or set TEST 1
echo $TEST

Related Solutions

Shell – Get default ubuntu motd in fish shell

Put this in your ~/.config/fish/config.fish:

function fish_greeting
  status --is-login
  if [ $status != 0 ] 
    cat /run/motd.dynamic
  end 
end

This will make sure that you don't get the double motd when logging in remotely.

Shell – Fish shell testing for existence of file in $PATH

Use type in fish like in Bourne-like shell:

if type -q figlet
  hostname | figlet
end

Or to limit to executables in $PATH (ignoring functions, builtins):

if command -s figlet > /dev/null
  hostname | figlet
end

Best Answer

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Shell – Get default ubuntu motd in fish shell

Shell – Fish shell testing for existence of file in $PATH

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