Add Check If The Local Server Is Running as a Postgres til

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
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@@ -507,6 +507,7 @@ _1082 TILs and counting..._
 - [Between Symmetric](postgres/between-symmetric.md)
 - [Capitalize All The Words](postgres/capitalize-all-the-words.md)
 - [Change The Current Directory For psql](postgres/change-the-current-directory-for-psql.md)
+- [Check If The Local Server Is Running](postgres/check-if-the-local-server-is-running.md)
 - [Check Table For Any Oprhaned Records](postgres/check-table-for-any-orphaned-records.md)
 - [Checking Inequality](postgres/checking-inequality.md)
 - [Checking The Type Of A Value](postgres/checking-the-type-of-a-value.md)

postgres/check-if-the-local-server-is-running.md

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+# Check If The Local Server Is Running
+
+An install of PostgreSQL comes with a number of utilities including the
+`pg_isready` command. This command can be used to check if the local PostgreSQL
+server is up, running, and ready to receive connections.
+
+If the server has not yet been started, running the command will result in a
+`no response` response.
+
+```bash
+$ pg_isready
+localhost:5432 - no response
+```
+
+In this case, the `pg_ctl` command can be used to start the server.
+
+```bash
+$ pg_ctl -D $HOME/.asdf/installs/postgres/12.3/data start
+waiting for server to start....
+
+...
+
+ done
+server started
+```
+
+It tells us that the server is started and we can confirm that by again running
+`pg_isready`.
+
+```bash
+$ pg_isready
+localhost:5432 - accepting connections
+```
+
+This command is most useful as part of a script, such as in a CI environment.
+In that case, you may not want it writing to `stdout`, you just want to use the
+command's exit code. For that, you can tack on the `--quiet` flag.
+
+```
+$ pg_isready --quiet
+```
+
+[source](https://www.postgresql.org/docs/current/app-pg-isready.html)