Square brackets

[IMAUser]

Hi ,

In UNIX shell scripting, I have seen double and single square brackets.
eg . if [[ $VAR -eq $VALUE ]] then
....
fi
As well as
if [ $VAR -eq $VALUE ] then
...
fi

Can someone tell me where to use double brackets and why.

Thanks.

 

[williamu]

Hi,

The [[ ]] construct is the shell equivalent of [ ]. This is the extended test command, adopted from ksh88.

Also, oo expansion or word splitting takes place between [[ and ]], but there is parameter expansion and command substitution.

HTH


William
Software Engineer
ICQ No. 56047340