Convert variable name list to comma separated variable names

This trick is quite useful for SPSS. Let say I have 50 variables that I want to sum up the values by using SUM(var1,var2, ...) in Transform > Compute variable..., converting the list:

var1
var2
...
var50

to

var1,var2,...,var50

then

SUM(var1,var2,...var50)

is quite tedious.

I found this nice command line from http://www.shellhacks.com/ (in Linux, of course). Save your list in a file, say temp_file, then

echo $(awk 'NR > 1{print line", "}{line=$0;}END{print $0" "}' temp_file) > new_file

Your comma separated variable names are ready in new_file. Thanks, penguin.