1 files changed, 14 insertions, 0 deletions
diff --git a/tecat.lua b/tecat.lua
new file mode 100755
index 0000000..e287658
--- /dev/null
+++ b/tecat.lua
@@ -0,0 +1,14 @@
+#!/usr/local/bin/lua52
+-- Replace all control characters with printable representations as in SciTECO.
+-- These characters are printed in reverse using ANSI escape sequences.
+-- This is especially useful as the diff textconv filter for Git as in
+-- git config --global diff.teco.textconv tecat
+local file = #arg > 0 and io.open(arg[1], 'rb') or io.stdin
+while true do
+	local buf = file:read(1024)
+	if not buf then break end
+	io.write((buf:gsub("[\00-\08\11\12\14-\31]", function(c)
+		c = c:byte()
+		return "\27[7m"..(c == 27 and '$' or '^'..string.char(c+0x40)).."\27[27m"
+	end)))
+end