Instead of writing a multiline if/then/else/fi construct you can do that by one line

[[ test_condition ]] && if_true_do_this || otherwise_do_that
instead of writing: if [[ "$1" == "$2" ]]; then echo "$1 is equal $2" else echo "$1 differs from $2" fi do write: [[ "$1" == "$2" ]] && echo "$1 is equal $2" || echo "$1 differs from $2"

By: stallmer
2009-02-20 21:45:21

1 Alternatives + Submit Alt

  • This will perform one of two blocks of code, depending on the condition of the first. Essentially is a bash terniary operator. To tell if a machine is up: ping -c1 machine { echo succes;} || { echo failed; } Because of the bash { } block operators, you can have multiple commands ping -c1 machine && { echo success; }|| { echo failed;; } Tips: Remember, the { } operators are treated by bash as a reserved word: as such, they need a space on either side. If you have a command that can fail at the end of the true block, consider ending said block with 'false' to prevent accidental execution Show Sample Output

    true && { echo success;} || { echo failed; }
    clockworkavian · 2009-04-02 01:49:25 1

What Others Think

[[ true ]] && false || echo "Not exactly the same."
silas · 638 weeks and 2 days ago
you can put an if construct all on one line; if [[ test_condition ]]; then do_stuff_here; else do_other_stuff_here; fi one advantage of using the actual if-statement is that you can add things in either clause without needing to use a set of braces. If you wanted to do it with braces, though, you could do: [[ test_condition ]] && { true_stuff_1; true_stuff_2; } || { false_stuff_1; false_stuff_2; }
woxidu · 637 weeks and 2 days ago
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ChelseaSCripe · 8 weeks and 3 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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