Can I put more than 1 condition in if?

Question

Is it possible to put more than 1 condition in an if statement?

if [ "$name" != "$blank" && "$age" == "$blank" ]; then

Is it possible? If not how am I supposed to do that?

Community · Accepted Answer · 2017-04-13 12:36:49Z

With [ expression ] (POSIX Standard) syntax you can use the following:

if [ "$name" != "$blank" ] && [ "$age" = "$blank" ]; then echo true fi

But in [[ expression ]] syntax you can use both conditions:

if [[ $name != "$blank" && $age == "$blank" ]]; then echo true! fi

Two advantages of [[ over [:

No word splitting or glob expansion will be done for [[, and therefore many arguments need not be quoted (with the exception of the right-hand side of == and !=, which is interpreted as a pattern if it isn't quoted).
[[ easier to use and less error-prone.

Downside of [[: it is only supported in ksh, bash and zsh, not in plain Bourne/POSIX sh.

My reference and good page to comparing [[ and [: bash FAQ

You mention that [ is POSIX standard. It's worth pointing out that [[ isn't. But if you're using other BASH features anyway, then def. use [[, it's better. (e.g. the bash-completion project coding standards mandate use of [[ ]].) — Peter Cordes
– Peter Cordes, Commented Jan 11, 2015 at 13:28

Community · Accepted Answer · 2017-04-13 12:36:52Z

4

Yet another possibility not mentioned by @SepahradSalour is to use -a operator:

if [ "$name" != "$blank" -a "$age" = "$blank" ]; then

BTW, be sure to quote properly all variables separately.

1

answered Jan 11, 2015 at 12:46

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