Don't abort when backup files already exist. Don't allow alternative names.
Rationale:
- When the user wants to revert, he shouldn't be stopped from doing
this just because some old backups will be overwritten.
- To not clobber important files by accident, alternative names for backup
files were disabled. As the backup target now has a fixed name, the user
doesn't have to be informed about the backup copy (unless --verbose)
#!/bin/sh
hg init
mkfifo p
hg serve --stdio < p &
P=$!
(echo lock; echo addchangegroup; sleep 5) > p &
Q=$!
sleep 1
kill -HUP $P
sleep 1
ls .hg