file_get_contents -- Reads an entire file into a string.
The function form reads an entire file and sets its contents to the variable. The subroutine form reads an entire file and outputs its contents to the standard output. The stream form reads a file name for each line and outputs its contents to the standard output.
// 1. Function form.
func::file_get_contents(string* variable, string filename)
// 2. Subroutine form.
sub::file_get_contents(string filename) > output
// 3. Stream form.
stream::file_get_contents() < input > output
sub::print hello > "${TMPDIR}/foo"
func::file_get_contents variable "${TMPDIR}/foo"
echo "${variable}" # => hello
sub::print hello > "${TMPDIR}/foo"
sub::file_get_contents "${TMPDIR}/foo" # => hello
sub::print hello > "${TMPDIR}/foo"
sub::print world > "${TMPDIR}/bar"
{ echo "${TMPDIR}/foo"; echo "${TMPDIR}/bar"; } | \
stream::file_get_contents # => helloworld