UNIX for Dummies Questions & Answers

Hi, i'm beginner in this area, so i've studied to hard, but still there are a lot of things that i do not understand like:

for example

Code:

cd /globall/okl/codelib/inqload/old unzip REL0003.zip -d /globall/okl/codelib/inqload

1.How many lines of commands are there?
2. Which is the function of command -d in from of that line?


other question...

Code:

if [ $# -lt 2 ]; then
 exit 1;
fi;

this is the first step in a some script, and i misunderstand the the first line.

Thanks, if anyone want to help me.

Moderator's Comments:

Please use code tags next time for your code and data.

there are three commands and not in the correct order ..

Code:

-d /globall/okl/codelib/inqload ( may be syntax error)
cd /globall/okl/codelib/inqload/old
unzip REL0003.zip

// checks if the directory inqload exists or not

Code:

[[ -d /globall/okl/codelib/inqload ]]

// if exists change to specified directory

Code:

cd /globall/okl/codelib/inqload/old

//unzip the zip file

Code:

unzip REL0003.zip

Code:

if [ $# -lt 2 ]; then
exit 1;
fi;

$# = number of command line arguments for the script
exit the script if $# is less than 2

Actually it is one single command:

Code:

cd somewhere nowhere nowhere

If there were a semicolon in front of the unzip, it were two commands:

Code:

cd somewhere; unzip sth -d targetdir

In this case "somewhere" equals "targetdir", so it is somewhat pointless.

Further to Other Posters:

There are excess semi-colons in the post. This is Shell not Oracle or Perl. Should be:

Code:

if [ $# -lt 2 ]
then
    exit 1
fi

The script checks whether the number or parameters supplied to the script is less than two, and exits with "exit 1" if this condition is not matched.

Note that Post #3 highlights a missing semi-colon. In the correct context, a semi-colon is an abbreviation for a line break. It it best practice to avoid semi-colons mid-line and to definitely not use semi-colons at the end of a line (one special syntax to the find command excluded).

Hi again, thanks to all of you, it were helpfull to me. I need to study harder, without doubs.