Last time I actually used it, there were no file locking issues.
New issue?
box$ echo "New issue description" >> issue_list.txt
Each night, triage new issues and number each one.
Update?
box$ grep "keyword" issue_list.txt then once you have the item number,
box$ ./update_list $task_id "New text" (update_list.sh was a quickie sed script)
It was locked for as long as it took to do a read or write. Nightly triage and weekly project meetings filed off the rough edges. Worked surprisingly well.