$ \textbf{export HGMERGE=merge}
$ \textbf{echo 'XXX this is broken and must be fixed'}
XXX this is broken and must be fixed
$ \textbf{hg merge}
merging letter.txt
merge: warning: conflicts during merge
merging letter.txt failed!
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges
$ \textbf{cat letter.txt}
Greetings!

I am Shehu Musa Abacha, cousin to the former
=======
I am Alhaji Abba Abacha, son of the former

Nigerian dictator Sani Abacha.