Shell Programming and Scripting

The leading "$ " is the prompt, so you don't type that.

Have you covered variables and how they work and how they are expanded by the shell?

You can do alot of playing around with variables purely with "echo"

Code:

FOO=foo
BAR=bar
echo $FOO
echo $BAR
echo $FOO $BAR
echo $FOO                         $BAR
echo "$FOO                        $BAR"

and some more

Code:

FLIM="flim         "
FLAM="        flam"
echo $FLIM
echo $FLAM
echo "$FLIM"
echo "$FLAM"
echo $FLIM $FLAM
echo "$FLIM $FLAM"

yes i have been through variables.

enter after the leading $

str1=abcd
test $str1 = abcd

then what can i do after this to get my exit result of 0.

$? is a variable that holds the return code of the last command.

Code:

echo $?

also

$$ is a variable that holds the current process id
$! is a variable that holds the pid of a process launched asynchronously
$0 holds the current script name
$1 ..... hold each argument from the command line
$@ holds all the command line arguments

Thanks prorter i got it now.

Any chance you being able to do any of the above scripts and then going through them with me.

I suggest you take the first one and have a go.

Start the file with

Code:

#!/bin/sh -x

call it something sensible and then do

Code:

chmod +x myscript.sh

so that the operating system know it can run it.

The -x option will make the shell spit out the detail of what it is really doing.

Iv created a file called filex and i have inserted the env details to it.

Did this by touch filex
then env > filex
checked to see if file has got the correct content in by cat filex.

Then iv created a script by creating a file - touch firstline
and the opening it in vi editor.

Does my first line not have to #!/bin/bash or what u have stated.

get stuck here...