CODEWITHSUNDEEP
linuxshellunix
orNehPraka
orNehPraka

Reputation: 443

Reading a parameter through command prompt (starts with "-")

I am facing a problem while reading input from command prompt in shell script. My script's name is status.ksh, and I have to take parameter from command prompt. This script accepts 2 parameter. 1st is "-e" and second is "server_name".

When I am running the script like this,

status.ksh -e server_name

echo $@

is giving output "server_name" only, where as expected output should be "-e server_name"

and echo $1 is giving output as NULL, where as expected output should be "-e".

Please guide me, how to read get the 1st parameter, which is "-e" .

Thanks & Regards

Upvotes: 0

Views: 92

Answers (2)

Karoly Horvath
Karoly Horvath

Reputation: 96266

The problem was caused by -e. This is a flag for echo.

   -e     enable interpretation of backslash escapes

Most of the unix commands allow -- to be used to separate flags and the rest of the arguments, but echo doesn't support this, so you need another command:

printf "%s\n" "$1"

If you need complex command line argument parsing, definitely go with getopts as Joe suggested.

Upvotes: 1

000
000

Reputation: 27247

Have you read this reference? http://www.lehman.cuny.edu/cgi-bin/man-cgi?getopts+1

You shouldn't use $1, $2, $@, etc to parse options. There are builtins that can handle this for you.

 Example 2 Processing Arguments for a Command with Options

 The following fragment of  a  shell  program  processes  the
 arguments  for a command that can take the options -a or -b.
 It also processes the option -o, which requires  an  option-
 argument:

   while getopts abo: c
   do
         case $c in
        a | b)   FLAG=$c;;
        o)       OARG=$OPTARG;;
        \?)      echo $USAGE
           exit 2;;
        esac
   done
   shift `expr $OPTIND - 1`

More examples:

http://linux-training.be/files/books/html/fun/ch21s05.html

http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.cmds/doc/aixcmds2/getopts.htm

http://www.livefirelabs.com/unix_tip_trick_shell_script/may_2003/05262003.htm

Upvotes: 0

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