package topkg

exists cmd is true if the executable of cmd can be found in the path and false otherwise.

must_exist cmd is cmd if the executable of cmd can be found in the path and an error otherwise.

run cmd runs the command cmd. std{i,o,err} are connected to the invoking process' standard channels. If err is specified stderr is redirected to the given file (e.g. File.null).

run_status cmd is like run, but doesn't error on non-zero exit status.

The type for run statuses, the command that was run and the run status.

success r is:

• Ok v if r = Ok (v, (_, `Exited 0))
• Error _ otherwise. Non `Exited 0 statuses are turned into an error message.

The type for representing the standard output of a command run.

out_string ~trim o captures the standard output o as a string. If trim is true (default) the result is passed through String.trim.

out_lines ~trim is like out_string but the result is cut on newlines ('\n').

out_file f o writes the standard output o to file f.

out_stdout o redirects the standard output o to the current process standard output.

to_string is (out_string ?trim o |> success).

to_lines ?trim o is (out_string ?trim o |> success).

to_file f o is (out_file f o |> success)

run_out cmd represents the standard output of the command run cmd. std{i,err} are connected to the invoking prcoess stream and standard output can be consumed with to_string, to_lines or to_file. If err is specified stderr is redirected to the given file.