ptx: add page (#2977)

pages/linux/ptx.md

@@ -0,0 +1,23 @@
+# ptx
+
+> Generate a permuted index of words from one or more text files.
+
+- Generate a permuted index where the first field of each line is an index reference:
+
+`ptx --references {{path/to/file}}`
+
+- Generate a permuted index with automatically generated index references:
+
+`ptx --auto-reference {{path/to/file}}`
+
+- Generate a permuted index with a fixed width:
+
+`ptx --width={{width_in_columns}} {{path/to/file}}`
+
+- Generate a permuted index with a list of filtered words:
+
+`ptx --only-file={{path/to/filter}} {{path/to/file}}`
+
+- Generate a permuted index with SYSV-style behaviors:
+
+`ptx --traditional {{path/to/file}}`