diff --git a/bash/rest.zip b/bash/rest.zip
new file mode 100644
index 0000000..2070a6d
Binary files /dev/null and b/bash/rest.zip differ
diff --git a/c/task.c b/bash/train_bash/concurrente.sh
old mode 100644
new mode 100755
similarity index 100%
rename from c/task.c
rename to bash/train_bash/concurrente.sh
diff --git a/c/pause b/c/pause
new file mode 100755
index 0000000..63bfa99
Binary files /dev/null and b/c/pause differ
diff --git a/c/pause.c b/c/pause.c
new file mode 100644
index 0000000..186cb20
--- /dev/null
+++ b/c/pause.c
@@ -0,0 +1,6 @@
+#include <unistd.h>
+
+int main(void) {
+    pause();
+    return 0;
+}
diff --git a/c/task.h b/c/task.h
deleted file mode 100644
index e69de29..0000000
diff --git a/python/fork.py b/python/fork.py
new file mode 100755
index 0000000..afa1e9d
--- /dev/null
+++ b/python/fork.py
@@ -0,0 +1,14 @@
+#!/usr/bin/python3
+
+import os, sys
+
+ret = os.fork()
+if ret == 0:
+    print("child process: pid={}, parent process's pid={}".format(os.getpid(), os.getppid()))
+    os.execve("/bin/echo", ["echo", "hello from pid={} ".format(os.getpid())], {})
+    exit()
+elif ret > 0:
+    print("parent process: pid={}, child process's pid={}".format(os.getpid(), ret))
+    exit()
+
+sys.exit(1)
diff --git a/python/spawn.py b/python/spawn.py
new file mode 100755
index 0000000..e5bfe18
--- /dev/null
+++ b/python/spawn.py
@@ -0,0 +1,6 @@
+#!/usr/bin/python3
+
+import os
+
+os.posix_spawn("/bin/echo", ["echo", "echo", "created by posix_spawn()"], {})
+print("created echo command")