update: adopted new output options. Various optimizations.

docs/Commands.md

@@ -6,6 +6,22 @@ The `sk-az-tools` package may act as a CLI tool that provides various commands f
 - Azure Resource Manager
 - Azure DevOps Services
 
+## Global Options
+
+These options apply to all commands unless stated otherwise:
+
+- `--query`, `-q` <jmespath> - Apply JMESPath filter before output rendering.
+- `--output`, `-o` <format> - Output format: `table|t|alignedtable|at|prettytable|pt|tsv`.
+- `--columns`, `-C` <definition> - Column selection for table outputs:
+	- `col1` - Select column (case-insensitive match), keep raw header label.
+	- `col1:` - Select column (case-insensitive match), use auto-generated header label.
+	- `col1: Label 1` - Select column (case-insensitive match), use custom header label.
+	- Prefix token with `=` for exact column-name match: `=col1`, `=col1:`, `=col1:Label`.
+	- Tokens are comma-separated and rendered in the specified order.
+- `--help`, `-h` - Show command help.
+
+Note: `rest --header` is a command-specific HTTP header option and is unrelated to `--columns`.
+
 ## Login
 
 **Command name:** `login`