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diff --git a/manual/index.html b/manual/index.html index c3f5e646..0d88f5af 100644 --- a/manual/index.html +++ b/manual/index.html @@ -147,9 +147,17 @@ parsed as a sequence of whitespace-separated JSON values which are passed through the provided filter one at a time. The output(s) of the filter are written to standard output, as a sequence of newline-separated JSON data.</p> +<p>The simplest and most common filter (or jq program) is <code>.</code>, +which is the identity operator, copying the inputs of the jq +processor to the output stream. Because the default behavior of +the jq processor is to read JSON texts from the input stream, +and to pretty-print outputs, the <code>.</code> program's main use is to +validate and pretty-print the inputs. The jq programming +language is quite rich and allows for much more than just +validation and pretty-printing.</p> <p>Note: it is important to mind the shell's quoting rules. As a general rule it's best to always quote (with single-quote -characters) the jq program, as too many characters with special +characters on Unix shells) the jq program, as too many characters with special meaning to jq are also shell meta-characters. For example, <code>jq "foo"</code> will fail on most Unix shells because that will be the same as <code>jq foo</code>, which will generally fail because <code>foo is not @@ -166,6 +174,8 @@ program.</p> <li>Powershell: <code>jq '.[\"foo\"]'</code></li> <li>Windows command shell: <code>jq ".[\"foo\"]"</code></li> </ul> +<p>Note: jq allows user-defined functions, but every jq program +must have a top-level expression.</p> <p>You can affect how jq reads and writes its input and output using some command-line options:</p> <ul> |