Shell Programming and Scripting

Hi
I am new to this forum. Please forgive me, If I am wrong anywhere. I am trying to understand the below code. Can anyone help in understanding what is ${#ST} here. Is that the value of the first parameter??...what is exit 1 mean. Any clarification is greatly appreciated.

export ST=$1
export EN=$2
if [ ${#ST} -eq 0 ]
then
echo ${#ST}
echo ${ABORT} " START_STEP environment variable must be present"
echo "Process cannot be executed"
exit 1
fi
if [ ${#EN} -eq 0 ]
then
echo ${ABORT} " END_STEP environment variable must be present"
echo "Process cannot be executed"
exit 1
fi

Thank you,
Sudha

${#ST} gives the length of the string value of the variable ST.
For example:

Code:

> ST='value'
> echo ${#ST}
5
>

Jean-Pierre.

Hi Jean-Pierre
Thank you for your prompt response. Even I want to know what is exit 1 there.
Thaks once again
sudha

The 'exit' command is how programmers should end their programs. It is the cleaner way to program. That said, if a program runs normally and ok, the last line would be an

Code:

exit 0

If there were problems, and in your case you are checking for two kinds of problems, you should terminate the script execution with

Code:

exit 1

The reason for this is that you can tell if there was a previous problem in the prior executed program/script. Code like the following:

Code:

if [ "$?" -ne 0 ]
   then
   echo "previous program exited with an error !! "
fi

As time goes on, you could provide more info by associating error numbers to error text. One you probably see a lot on the internet is the "404" meaning page not found. Some websites know to anticipate a 404, and therefore provide better messages than just "error - page not found".