fakepython.sh

#!/bin/bash

#
# Copyright (c) 2021 Neruthes.
# Released under GNU GPLv2.
#

### Initialize config vars
DefaultPythonVer=3

### Read config
source /etc/fakepython/conf

echo "Welcome to FakePython.">&2
echo "You should put me at '/usr/bin/python',">&2
echo "So I can decide the version expectation of the incoming script.">&2
echo "This is a mitigation against stupid scripts who put this path in their shebang.">&2
echo "Decisions are made by looking up '/etc/fakepython/list.force{2,3}*' for their paths.">&2
echo "">&2

SRCPATH=$(realpath $1)
echo "The script is: $SRCPATH">&2

ALLARGS="$@"
OTHERARGS=""
COUNT=0
for i in $ALLARGS; do
    if [[ $COUNT == 0 ]]; then
        COUNT=999
    else
        OTHERARGS="$OTHERARGS $i"
    fi
done
echo "The arguments are:">&2
echo "    $OTHERARGS">&2
echo "">&2

echo "Can we find this in 'list.force2'?"
if [[ "$(cat /etc/fakepython/list.force2* | grep "^$SRCPATH\$")" == "" ]]; then
    echo "> Cannot find it.">&2
else
    echo "> YES!">&2
    echo "--------------------------------------------------------------------">&2
    exec /usr/bin/python2 "$@"
fi
echo "">&2

echo "Can we find this in 'list.force3'?"
if [[ "$(cat /etc/fakepython/list.force3* | grep "^$SRCPATH\$")" == "" ]]; then
    echo "> Cannot find it.">&2
else
    echo "> YES!">&2
    echo "--------------------------------------------------------------------">&2
    exec /usr/bin/python3 "$@"
fi
echo "">&2

 
echo "">&2
echo "If we reach here, there is no specific configuration for $SRCPATH">&2
echo "Defaulting to /usr/bin/python$DefaultPythonVer">&2

echo "exec /usr/bin/python$DefaultPythonVer \"$@\"">&2
echo "--------------------------------------------------------------------">&2

exec /usr/bin/python$DefaultPythonVer "$@"