added install script

README.md

@@ -9,4 +9,17 @@ confirmation. It requires `kakoune` since we use `kak -f` to perform the
 replacement.
 
 To use the script, simply provide a path to a `PKGBUILD` or its parent
-directory as the argument.
+directory as the argument. If no argument is given, the current working
+directory is used.
+
+The following installation script is provided as a convenience. You can
+copy this code into a POSIX shell to install `update-integrity`.
+
+```sh
+#!/bin/sh
+
+script="https://git.sr.ht/~ficd/pkgbuild-update-integrity/blob/main/update-integrity"
+curl "$script">update-integrity
+chmod +x update-update-integrity
+sudo cp -f update-integrity /usr/bin/update-integrity
+```

install.sh

@@ -0,0 +1,7 @@
+#!/bin/sh
+
+script="https://git.sr.ht/~ficd/pkgbuild-update-integrity/blob/main/update-integrity"
+curl "$script">update-integrity
+chmod +x update-update-integrity
+sudo cp -f update-integrity /usr/bin/update-integrity
+