write a shell script to send a message to a user on the machine

1 files changed, 22 insertions, 0 deletions

diff --git a/EXAM.md b/EXAM.md
index 210765e..f02f49a 100644
--- a/EXAM.md
+++ b/EXAM.md
@@ -124,3 +124,25 @@ Some examples of IPC mechanisms are:
 * socket: A TCP/UDP can be used for streaming data across a network.
 * UNIX domain socket: Can be used to stream data from one process to another on a host.
 * Pipes: A program can write to stdout which can be piped into stdin of another process.
+
+
+# Write a shell script that searches the password file for an input name and sends that person a "hello" message.
+
+`/etc/passwd` format.
+
+| login | password set | uid | gid | comment | home dir | shell |
+
+
+```sh
+#!/bin/sh
+
+cd "$(dirname "$0")/.."
+USER=${1}
+
+if cat /etc/passwd | cut -d: -f1 | grep -E "^$USER"; then
+  echo "hello" | write "$USER"
+else
+  echo "I could not find '${USER}'"
+  exit 1
+fi
+```