apognu
Add support for all standard escape codes in /etc/issue
This PR attempts to add support for all escape codes (except \O: see below) in the agetty manual, usable in the /etc/issue file, in response to Arch Linux changing their default /etc/issue to require more fully-fledged support. This PR fixes #169.
I wasn't sure whether (or how) to add any tests, but tested locally with the following /etc/issue:
\e{halfbright}\e{yellow}\d \4 \4{lo} \6 \b \s \S \e[0m\S{BUILD_ID} \S{ANSI_COLOR}(\S{PRETTY_NAME}) \l \m \n \o \r \t \u \U \v
This lined up with the output from agetty.
I could not figure out how to find \O (DNS hostname: as reported by hostname -d) in Rust, so if you have any advice on this, please let me know.
Please also let me know if you'd like me to add or change anything, especially as I've never programmed in Rust before nor contributed to this project.
