Does the opposite of ashift. Or the opposite of apush, depending on how you look at it. Prepends list to the front of the array and returns the new number of elements in the array.
unshift(@ARGV, '-e') unless $ARGV[0] =~ /^-/;Note the LIST is prepended whole, not one element at a time, so the prepended elements stay in the same order. Usereverse to do the reverse.
Starting with Perl 5.14,unshift can take a scalar EXPR, which must hold a reference to an unblessed array. The argument will be dereferenced automatically. This aspect ofunshift is considered highly experimental. The exact behaviour may change in a future version of Perl.
To avoid confusing would-be users of your code who are running earlier versions of Perl with mysterious syntax errors, put this sort of thing at the top of your file to signal that your code will workonly on Perls of a recent vintage:
use 5.014;# so push/pop/etc work on scalars (experimental)Perldoc Browser is maintained by Dan Book (DBOOK). Please contact him via theGitHub issue tracker oremail regarding any issues with the site itself, search, or rendering of documentation.
The Perl documentation is maintained by the Perl 5 Porters in the development of Perl. Please contact them via thePerl issue tracker, themailing list, orIRC to report any issues with the contents or format of the documentation.