How to represent multiple conditions in a shell if statement?

Question

I want to represent multiple conditions like this: if [ ( $g -eq 1 -a "$c" = "123" ) -o ( $g -eq 2 -a "$c" = "456" ) ] then echo abc; else echo efg; fi but when I execute the script, it shows syntax error at line 15: `[' unexpected, where line 15 is the one showing if .... What is wrong with this condition? I guess something is wrong with the `()`.

Answer 1

First, I'm not sure what works in the single bracket [ ] test any longer ... modern versions of korn shell and bash encourage usage of the double bracket [[ ]]

Similar to your example above, see below.

Use && for logical AND and || for logical OR ..

This worked under both ksh and bash ...

a=1

b=4

c=3

d=4

if [[ $a -eq 1 && $b -eq 2 || $c -eq 3 && $d -eq 4 ]]

then

echo ok

else

echo "No go"

fi

ok

Also, this is shorthand for the above - this works also if you don't need an "else" logical branch:

$ [[ $a -eq 1 && $b -eq 2 || $c -eq 3 && $d -eq 4 ]] && echo ok

ok