Re: Can $1 be set in a script?

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.

--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@xxxxxxxxxx
.

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