Simplify sha256sum checking example
The previous code didn't consider other languages and hid the output of failures. For example
```
$ LANG=es_ES.UTF-8 sha256sum -c sha256sum.txt
oauth2-proxy-v7.1.3.linux-amd64/oauth2-proxy: La suma coincide
```
commit1c151b4b27358ed41d628f7f7a8ae1ddf2c704da
authorIan Hunter <ihunter@vidangel.com>
dateMon 21 Jun 2021, 10:44 (5 years ago)
parentc2325ec
docs/docs/installation.md+1−1
@@ -17,7 +17,7 @@ slug: /
1717Prebuilt binaries can be validated by extracting the file and verifying it against the `sha256sum.txt` checksum file provided for each release starting with version `v3.0.0`.
1818
1919```
20−$ sha256sum -c sha256sum.txt 2>&1 | grep OK
20+$ sha256sum -c sha256sum.txt
2121oauth2-proxy-x.y.z.linux-amd64: OK
2222```
2323