install problem
Hi folks, first time user here, I am having problems with the install on the mac os, using zsh. 

smatm0013:taskopen:% sudo make PREFIX=/usr                                                    <master ✗>
gzip -c doc/man/taskopen.1 > doc/man/taskopen.1.gz
gzip -c doc/man/taskopenrc.5 > doc/man/taskopenrc.5.gz
sed s',#PATH_EXT=.*,&\nPATH_EXT=/usr/share/taskopen/scripts,' taskopen > taskopen.pl
sed -i'.bak' s',/usr/bin/perl,/usr/bin/perl,' taskopen.pl

smatm0013:taskopen:% sudo make PREFIX=/usr install                                            <master ✗>
gzip -c doc/man/taskopen.1 > doc/man/taskopen.1.gz
gzip -c doc/man/taskopenrc.5 > doc/man/taskopenrc.5.gz
sed s',#PATH_EXT=.*,&\nPATH_EXT=/usr/share/taskopen/scripts,' taskopen > taskopen.pl
sed -i'.bak' s',/usr/bin/perl,/usr/bin/perl,' taskopen.pl
mkdir -p //usr/bin
install -m 0755 taskopen.pl //usr/bin/taskopen
install: //usr/bin/taskopen: Operation not permitted
make: *** [install] Error 71

Those // in front of usr/bin doesn't look right to me, I will admit that the Makefile knowledge is pretty rusty these days. 