Update cheatsheets

keep-header

@@ -0,0 +1,25 @@
+---
+syntax: markdown
+tags: [tldr, common]
+source: https://github.com/tldr-pages/tldr.git
+---
+# keep-header
+
+> Keep first line untouched by a command, passing it directly to `stdout`.
+> More information: <https://github.com/eBay/tsv-utils#keep-header>.
+
+- Sort a file and keep the first line at the top:
+
+`keep-header {{path/to/file}} -- sort`
+
+- Output first line directly to `stdout`, passing the remainder of the file through the specified command:
+
+`keep-header {{path/to/file}} -- {{command}}`
+
+- Read from `stdin`, sorting all except the first line:
+
+`cat {{path/to/file}} | keep-header -- {{command}}`
+
+- Grep a file, keeping the first line regardless of the search pattern:
+
+`keep-header {{path/to/file}} -- grep {{pattern}}`