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Revision 1 as of 2007-05-02 23:12:30
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Editor: redondos
Revision 2 as of 2007-08-24 12:19:38
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Editor: GreyCat
Comment: fix a typo in the second legacy-shell example
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            argn=arg             argn=$arg


How can I access positional parameters after $9?

Use ${10} instead of $10. This works for ["BASH"] and KornShell, but not for older BourneShell implementations. Another way to access arbitrary positional parameters after $9 is to use for, e.g. to get the last parameter:

    for last
        : # nothing

    echo "last argument is: $last"

To get an argument by number, we can use a counter:

    n=12        # This is the number of the argument we are interested in
    for arg
        if [ $i -eq $n ]
        i=`expr $i + 1`
    echo "argument number $n is: $argn"

This has the advantage of not "consuming" the arguments. If this is no problem, the shift command discards the first positional arguments:

    shift 11
    echo "the 12th argument is: $1"

Although direct access to any positional argument is possible this way, it's hardly needed. The common way is to use getopts(3) to process command line options (e.g. "-l", or "-o filename"), and then use either for or while to process all arguments in turn. An explanation of how to process command line arguments is available here: http://www.shelldorado.com/goodcoding/cmdargs.html

BashFAQ/025 (last edited 2014-04-24 10:02:07 by pgas)