diff --git a/run-command.c b/run-command.c
index f72e72cce7..da02553f44 100644
--- a/run-command.c
+++ b/run-command.c
@@ -210,9 +210,9 @@ static char *locate_in_PATH(const char *file)
 	return NULL;
 }
 
-static int exists_in_PATH(const char *file)
+int exists_in_PATH(const char *command)
 {
-	char *r = locate_in_PATH(file);
+	char *r = locate_in_PATH(command);
 	int found = r != NULL;
 	free(r);
 	return found;
diff --git a/run-command.h b/run-command.h
index af1296769f..aad027984d 100644
--- a/run-command.h
+++ b/run-command.h
@@ -182,6 +182,18 @@ void child_process_clear(struct child_process *);
 
 int is_executable(const char *name);
 
+/**
+ * Check if the command exists on $PATH. This emulates the path search that
+ * execvp would perform, without actually executing the command so it
+ * can be used before fork() to prepare to run a command using
+ * execve() or after execvp() to diagnose why it failed.
+ *
+ * The caller should ensure that command contains no directory separators.
+ *
+ * Returns 1 if it is found in $PATH or 0 if the command could not be found.
+ */
+int exists_in_PATH(const char *command);
+
 /**
  * Start a sub-process. Takes a pointer to a `struct child_process`
  * that specifies the details and returns pipe FDs (if requested).