This program is designed to let you play with the Perl YAML modules in an
interactive way. When you to type in Perl, you get back YAML. And vice versa.
By default, every line you type is a one line Perl program, the return value of
which will be displayed as YAML.
To enter multi-line Perl code start the first line with ; and use as many
lines as needed. Terminate with a line containing just ;.
To enter YAML text, start with a valid YAML separator/header line which is
typically ---. Use === to indicate that there is no YAML header. Enter as
many lines as needed. Terminate with a line containing just ....
To read in and process an external YAML file, enter < filename. The ysh will
also work as a standalone filter. It will read anything on STDIN as a YAML
stream and write the Perl output to STDOUT. You can say (on most Unix systems):
cat yaml.file | ysh | less