May 21, 2009

Deciphering lines of code

Hey everyone I don't know if this is the right place to ask this question but I am trying to learn what different lines of code do and I need some help. I am looking at the Save command specifically. It was written to save files and back then up to a directory for later backup usage. The problem that I am having is in the first part of the code. For instance on this line

if [! -d $1];then echo $1 is not a directory; exit 1; fi

I know the fi means that the line is finished and the echo is a command to run the $1 file but what is the first part? Any help will be appreciated. Thanks