Update cheatsheets

sponge

@@ -0,0 +1,17 @@
+---
+syntax: markdown
+tags: [tldr, common]
+source: https://github.com/tldr-pages/tldr.git
+---
+# sponge
+
+> Soak up the input before writing the output file.
+> More information: <https://manned.org/sponge>.
+
+- Append file content to the source file:
+
+`cat {{path/to/file}} | sponge -a {{path/to/file}}`
+
+- Remove all lines starting with # in a file:
+
+`grep -v '^{{#}}' {{path/to/file}} | sponge {{path/to/file}}`