Akin to make and makefile (but not really), this is a script runner called run that runs a runfile in the current directory. To install, create a symbolic link to run.sh called run somewhere in your $PATH.
The idea is that a runfile is basically a switch that runs subcommands. That way, you can have runfiles laying around that don't need to be executable or on your $PATH. This is convenient for storing collections of shell commands that are specific to particular directories.
In normal usage, the first argument must be the name of a subcommand (i.e., one of the comparands defined in the case block of the runfile). This can be followed by optional arguments, which are available to the subcommands as "${@}".
To initialize or edit the runfile for the current directory, simply call run -e.
For added convenience, you can add an alias to your .bashrc for quickly listing the run subcommands in the current directory's runfile:
alias runls="grep -Eo '^\w+\s*).*' runfile | sed 's/)[# ]*/|/' | column -s '|' -t"
Note that subcommands longer than one line can place a helpful comment or usage statement following the subcommand switch, e.g.:
fizzbuzz) # run the classic fizzbuzz algorithm
for num in {1..100}; do
...
Comments like this will be displayed by the runls alias above in a column-formatted table.