Shell Programming and Scripting

#/bin/sh

set -A array "are" "you" "there";

The standard Unix shell does not have arrays, so you should use a shebang that indicates which shell you are using.

That syntax is, I believe, ksh93, so your script should begin with:

Code:

#!/usr/bin/ksh93

(Or wherever your ksh93 is hiding.)

for ( i = 0 ; i < ${#array[@]} ; i++ )

That is non-standard syntax; it isn't even correct for bash and ksh93 which use something similar:

Code:

for (( i = 0 ; i < ${#array[@]} ; i++ ))

I think that's right; I avoid non-standard syntax when it offers nothing more than the standard.

The following is not standard because of the array, but the for syntax is standard:

Code:

for i in "${!array[@]}"

do
echo ${array[$i]}
done

tci001wasd02 $ sh -vx array_for.sh
#/bin/sh

set -A array "are" "you" "there";
+ set -A array are you there

for ( array_for.sh[5]: 0403-057 Syntax error at line 5 : `(' is not expected.

tci001wasd02 $ cat array_for.sh
#/bin/ksh93

set -A array "are" "you" "there";

I would use the more portable (though arrays are not standard) form of assigning an array:

Code:

array=( are you there )   ## doesn't work in ksh88, AFAIK

for (( i = 0 ; i < ${#array[@]} ; i++ ))
do
echo ${array[$i]}
done
tci001wasd02 $ sh -vx array_for.sh
#/bin/ksh93

set -A array "are" "you" "there";
+ set -A array are you there

for ((array_for.sh[5]: 0403-057 Syntax error at line 5 : `(' is not expected.

Then use the standard syntax.

(That works for me in ksh93; perhaps you are using a different version of ksh93. All the more reason to use the standard syntax; it will work in all versions and other shells.)

for i in "${!array[@]}"

Both forms give you all the elements in the array. You have to select the ones you want inside the loop.

Always use the standard syntax when possible without losing efficiency. Non-standard features may (and often do) change from one verion of a shell to the next.