archiso/mkarchiso: general bash improvements

Quote all variables.
Terminate option processing using '--' for commands that support it.
Do not hardcode file descriptor.
Compare integers with arithmetic comparison instead of string comparison.
Replace echo with printf.
Use heredoc for usage text.
Don't print INFO messages when quiet is set.
Export SOURCE_DATE_EPOCH.

0 files changed, 0 insertions, 0 deletions