From a4ad1ffa252d2e5d74eea8c56479f6bf27e316e7 Mon Sep 17 00:00:00 2001
From: Tuomas Tynkkynen <tuomas@tuxera.com>
Date: Sat, 7 Jan 2017 19:36:45 +0200
Subject: [PATCH] nix-shell: Fix 'nix-shell --command' doing nothing without
 TTY

Regression from 8bddc3d4 ("Fix early removal of rc-file for nix-shell").
The removal of BASH_ENV causes nothing to be executed by bash if it
detects itself in a non-interactive context. Instead, just
use the same condition used by bash to launch bash differently.

According to bash sources, the condition (stdin and stder both
must be TTYs) is specified by POSIX so this should be pretty
safe to rely on.

Fixes #1171 on 1.11.
---
 scripts/nix-build.in | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/scripts/nix-build.in b/scripts/nix-build.in
index c7a60623..bb61e1c1 100755
--- a/scripts/nix-build.in
+++ b/scripts/nix-build.in
@@ -17,7 +17,8 @@ my $runEnv = $0 =~ /nix-shell$/;
 my $pure = 0;
 my $fromArgs = 0;
 my $packages = 0;
-my $interactive = 1;
+# Same condition as bash uses for interactive shells
+my $interactive = -t STDIN && -t STDERR;
 
 my @instArgs = ();
 my @buildArgs = ();