highlight.sh

#!/bin/bash
cat > delimiter.rtf <<EOF
{\\rtf1\\ansi\\ansicpg1251\\cocoartf1344\\cocoasubrtf360
{\\fonttbl\\f0\\fswiss\\fcharset0 Helvetica;}
{\\colortbl;\\red255\\green255\\blue255;}
\\paperw11900\\paperh16840\\margl1440\\margr1440\\vieww10800\\viewh8400\\viewkind0
\\pard\\tx566\\tx1133\\tx1700\\tx2267\\tx2834\\tx3401\\tx3968\\tx4535\\tx5102\\tx5669\\tx6236\\tx6803\\pardirnatural

\\f0\\fs24 \\cf0 \\
}
EOF

for filename in $(find . -name '*.rb'); do
  cat > head.rtf <<EOF
{\\rtf1\\ansi\\ansicpg1251\\cocoartf1344\\cocoasubrtf360
{\\fonttbl\\f0\\fswiss\\fcharset0 Helvetica;\\f1\\fnil\\fcharset0 MesloLGS-RegularForPowerline;}
{\\colortbl;\\red255\\green255\\blue255;}
\\paperw11900\\paperh16840\\margl1440\\margr1440\\vieww10800\\viewh8400\\viewkind0
\\pard\\tx566\\tx1133\\tx1700\\tx2267\\tx2834\\tx3401\\tx3968\\tx4535\\tx5102\\tx5669\\tx6236\\tx6803\\pardirnatural

\\f0\\fs24 \\cf0 \\
\\pard\\tx566\\tx1133\\tx1700\\tx2267\\tx2834\\tx3401\\tx3968\\tx4535\\tx5102\\tx5669\\tx6236\\tx6803\\pardirnatural

\\f1 \\cf0 $filename\\
\\
}
EOF
  pygmentize -f rtf -O 'fontface = Meslo LG S for Powerline' $filename > body.rtf
  textutil -cat rtf head.rtf body.rtf -output tmp.rtf
  test -f source.rtf && textutil -cat rtf source.rtf delimiter.rtf tmp.rtf -output source.rtf
  ! (test -f source.rtf) && mv tmp.rtf source.rtf
done

rm delimiter.rtf head.rtf body.rtf tmp.rtf