Shell Programming and Scripting

Hello again Gurus,
Can someone please direct me to an online source that specifically explains what characters like [ ! # {} ] mean within if statements? or scripts in general, I have found information about the different letter options you can specify for an if statment, but I get really confused with the ! in front of a -f or particularly this if [ $# -lt 1 ] at the beginning of a script when there have been no variables set.

I've learned the basic purpose of an if statement and case statement sort of, but the special characters are somehow omitted from the sources I've been looking at.

Any source for dummies or idiots like myself would be great!

Thanks so much.

Charlie.

This is a pretty extensive list/explanation of special characters:
http://www.tldp.org/LDP/abs/html/special-chars.html

As for:

Code:

if [ $# -lt 1 ]

$# indicates the number of command line arguments, so it's saying if there is less than 1 do something (probably exit with a usage message.)

Hi.

An entire chapter, just on special characters in scripting, Special Characters Found In Scripts and Elsewhere http://www.tldp.org/LDP/abs/html/special-chars.html ... cheers, drl

Thanks a lot, this is an excellent place to get started...

Charlie.