$ \textbf{echo 'this is my original thought' > oldfile}
$ \textbf{echo 'i have changed my mind' > newfile}
$ \textbf{diff -u oldfile newfile > tiny.patch}
$ \textbf{cat tiny.patch}


@@ -1 +1 @@
-this is my original thought
+i have changed my mind
$ \textbf{patch < tiny.patch}
patching file oldfile
$ \textbf{cat oldfile}
i have changed my mind