From c629c3a0f01b7b5ccaacf7fb85df10ae5d59de9b Mon Sep 17 00:00:00 2001 From: Martin Fischer Date: Sun, 28 Nov 2021 18:55:19 +0100 Subject: add shebang --- shebang | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100755 shebang diff --git a/shebang b/shebang new file mode 100755 index 0000000..09ecd76 --- /dev/null +++ b/shebang @@ -0,0 +1,32 @@ +#!/usr/bin/env python3 +""" +Reads a script with a shebang from standard input and executes it. +""" +import os +import subprocess +import sys + +# We are not using sys.stdin because it does internal buffering: +# sys.stdin.read(2) can read up to 8192 bytes, we however don't +# want that because we want everything after the shebang to be +# read by the subprocess. + +if os.read(0, 2) != b'#!': + sys.exit('expected #! shebang') + +line = b'' + +while True: + byte = os.read(0, 1) + if byte == b'': + sys.exit('unexpected EOF') + if byte == b'\n': + break + line += byte + +args = line.strip().split(maxsplit=1) +args.append('/dev/stdin') +subprocess.run(args) + +# the subprocess inherits the standard input file +# descriptor and interprets the remaining input -- cgit v1.2.3