Stall when command is not found

[sirolf2009]

I copied the example in the README.md and when I would try run it, it would just stall forever on waitFor(). The code is in xtend, which is a java dialect

// The command to run in a PTY...
val cmd = #["/bin/sh", "-l" ]
val env = #{"TERM" -> "xterm"}

val pty = PtyProcess.exec(cmd, env);

val os = pty.getOutputStream()
val is = pty.getInputStream()

new Thread[
	new BufferedReader(new InputStreamReader(is)).lines().forEach[println(it)]
].start()
new Thread[
	new BufferedReader(new InputStreamReader(pty.getErrorStream())).lines().forEach[System.err.println(it)]
].start()

println("Waiting")
// wait until the PTY child process terminates...
val result = pty.waitFor();

// free up resources.
pty.destroy();
println(result)

The logs aren't particularly useful

2018-11-01 10:59:44,262 [DEBUG ] ExtractedNative 93 │ Found /tmp/pty4j-linux-x86_64-8391184450079375244 in 0 ms
2018-11-01 10:59:44,262 [DEBUG ] ExtractedNative 98 │ Listed files in 0 ms
2018-11-01 10:59:44,262 [DEBUG ] ExtractedNative 109 │ Checked upToDate in 0 ms
2018-11-01 10:59:44,262 [DEBUG ] ExtractedNative 116 │ Cleared directory in 1 ms
2018-11-01 10:59:44,263 [DEBUG ] ExtractedNative 122 │ Copied [resources/com/pty4j/native/linux/x86_64/libpty.so] in 1 ms
2018-11-01 10:59:44,263 [INFO  ] ExtractedNative 126 │ Extracted pty4j native in 1 ms
waiting

So I wanted to see what the command actually does

$ /bin/sh -l                                                                                                                                              sirolf2009 <[email protected]> sort timeseries 
/bin/sh: 25: source: not found
$ ^C
$ exit
$

I get a source not found, and then a subshell. Which is probably why I was stalling, the subshell was waiting for input. So shouldn't I have seen /bin/sh: 25: source: not found in my console?

Details:
Pty4j v0.8.5

$ uname -a                                                                                                                              
Linux northpool2 4.9.0-8-amd64 #1 SMP Debian 4.9.110-3+deb9u6 (2018-10-08) x86_64 GNU/Linux