#!/bin/sed -f s/.*/Hello world/
As it has been explained quite well, self-contained sed scripts don't work well with /usr/bin/env. But even without
/usr/bin/env putting more than 1 argument after
sed might not work. See the following example of GNU sed 4.1.5 on Debian Lenny:
$ cat ./testsed #!/bin/sed -n -f /Hello/p $ echo Hello World | ./testsed /bin/sed: invalid option -- Usage: /bin/sed [OPTION]... (...)
However, it works when you combine the options into one, e.g.
#!/bin/sed -nf /Hello/p
$ echo Hello World | ./testsed Hello World