Protect file access within shell commands via a wrapper that adds cooperative locking.

This small tool decorates existing command(s) that work on a single text file (and assume unfettered access) with protections for concurrent accesses via file locking of a separate lock file, thereby providing support for simple transactions, with multiple concurrent reads, a singular write (and a command to update from read to write), and rollback of any updates done under the transaction.

• Bash
• flock for transaction support
• automated testing is done with bats - Bash Automated Testing System (https://github.com/bats-core/bats-core)

• The ./bin subdirectory is supposed to be added to PATH.