subcommand wrapper

echo

#!/bin/sh

SUBCOMMAND=$0-$1;
ORIGINAL_COMMAND=/bin/echo

command -v $SUBCOMMAND >/dev/null 2>&1 || {
    exec $ORIGINAL_COMMAND $*;
    exit 1;
}

exec $0-$*;
exit 1;

echo-hello

#!/bin/sh

echo "hello, world" $*

output.txt

$ ./echo test
test
$ ./echo hello
hello, world
$ ./echo hello test
hello, world test