Add Create A Filename With The Current Date as a Unix TIL

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
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@@ -1542,6 +1542,7 @@ If you've learned something here, support my efforts writing daily TILs by
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 - [Create A File Descriptor with Process Substitution](unix/create-a-file-descriptor-with-process-substitution.md)
+- [Create A Filename With The Current Date](unix/create-a-filename-with-the-current-date.md)
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unix/create-a-filename-with-the-current-date.md

@@ -0,0 +1,38 @@
+# Create A Filename With The Current Date
+
+I was recently working on a script to pull a scrubbed database dump using the
+`pg_dump` Postgres utility. Ultimately, the script does something like this to
+dump a remote database to a local file:
+
+```bash
+pg_dump \
+  -h host.region.rds.amazonaws.com \
+  -U db_username \
+  -d db_name \
+  -F c \
+  -f scrubbed-database-$(date +%Y-%m-%d).dump
+```
+
+Notice the last part of that command where we define the name of the dump file.
+It has a `$(...)` that is used to run and interpolate a command as part of the
+filename.
+
+Here is that `date` command run on its own:
+
+```bash
+$ date +%Y-%m-%d
+2025-04-02
+```
+
+In the above command, that would mean if I were to run it today, I'd get
+`scrubbed-database-2025-04-02.dump`.
+
+This approach can be used with any command where you are producing a file that
+you want to be dated or timestamped.
+
+Here is another example that incorporates the time as well:
+
+```bash
+$ touch $(date +%Y%m%d_%H%M%S)-migration.sql
+# => 20250402_092442-migration.sql
+```