Re: Can $1 be set in a script?

On Thu, 30 Mar 2006 13:44:57 -0900, floyd@xxxxxxxxxx (Floyd L.
Davidson) wrote:

larryalk <nobody@xxxxxxxxxxx> wrote:

To be clearer, assuming a script called with or without a $1
how can I can assign the (possibly non-existant) $1 to something?

Instead of

something=${1}

Do this,

if [ -z "${1}" ]
then
something="default string"
else
something="${1}"
fi

Ahem..., you said set $1 to something, and I'm saying set
something to $1 and then use $something everywhere in your
script that you would have used $1.

Or, you might want to do this instead (slightly different
results),

if [ 1 -gt ${#} ]
then
something="default string"
else
something="${1}"
fi


The first script will use the default if $1 is an empty string,
which means the script cannot intentionally be invoked with an
empty string, like this,

$ ./foo "" two three four

The second variation will only replace the original $1 if there
are *no* arguments. It would have to be invoked like this,

$ ./foo

to get the defaulted value for $something.

Note that the above use of brackets, {...}, is arbitrary and
makes no difference in the examples as written; however, the use
of double quotes, "...", is significant.

Thanks for your answer Floyd and I apologize for still being unclear.

Whether $1 and $2 already exist I, wish to assign a new variable to
them so I can use $1 and $2 in an existing_script.

The only script modification would be editing the variables at the top
which is better than re-working the entire script.

Larry

--
My real sig is much better.
.

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