diff --git a/nix/start-powerline.sh b/nix/start-powerline.sh
index 84fd072d8..52b00f763 100644
--- a/nix/start-powerline.sh
+++ b/nix/start-powerline.sh
@@ -1,76 +1,84 @@
 #!/usr/bin/env bash
 
+# Check if in an interactive shell
+# `test -t` tests if a file descriptor is open, 0 being stdin
+# Normally, a non-interactive shell will not have 0 FD bound
+# However, Buildkite still has 0 FD bound, so check if PS1 is empty
+if [[ ! -t 0 ]] || [[ -z "$PS1" ]]; then
+  return 0
+fi
+
 if test "$(uname)" = "Darwin" ; then
   COMM_CACHE="${XDG_CACHE_HOME:-$HOME/Library/Caches}/app.comm"
 else
   COMM_CACHE="${XDG_CACHE_HOME:-$HOME/.cache}/comm"
 fi
 
 mkdir -p "$COMM_CACHE"
 COMM_POWERLINE="$COMM_CACHE/enable-powerline"
 
 # Only emit this the first time, as it's suprising to the user for the prompt
 # to be replaced, but avoid emitting the warning on subsequent invocations
 if [[ ! -e "${COMM_POWERLINE}" ]]; then
   read -r \
     -p "Would you like to enable Powerline as the default bash prompt? [y/N] " \
     response
   case "$response" in
     [yY][eE][sS]|[yY])
       echo "1" > "${COMM_POWERLINE}"
       ;;
     *)
       touch "${COMM_POWERLINE}"
       ;;
   esac
 fi
 
 # If empty, user want's to use native prompt
 if [[ ! -s "${COMM_POWERLINE}" ]]; then
   return 0
 fi
 
 # Check if the powerline fonts are installed
 # If the font is missing then many of the glyphs will render as ?
 # Adapted from https://github.com/powerline/fonts/blob/master/install.sh
 if test "$(uname)" = "Darwin" ; then
   # MacOS
   font_dir="$HOME/Library/Fonts"
 else
   # Linux
   font_dir="${XDG_DATA_HOME:-$HOME/.local/share}/fonts"
   mkdir -p "$font_dir"
 fi
 
 if [[ ! -f "$font_dir/Droid Sans Mono for Powerline.otf" ]]; then
   if [[ ! -d "${powerline_fonts:-/doesnt-exist}" ]]; then
     echo "Unable to determine powerline fonts location" >&2
     return 1
   fi
 
   echo "Installing Powerline fonts" >&2
   find "$powerline_fonts" \
     \( -name "*.[ot]tf" -or -name "*.pcf.gz" \) -type f -print0 \
     | xargs -0 -n1 -I % cp "%" "$font_dir/"
 
   if test "$(uname)" = "Darwin" ; then
 
     if [[ "$TERM_PROGRAM" == "Apple_Terminal" ]]; then
       echo "For glyph support, please:
   Select Terminal > Preferences > Text > Font > Change > \
 Select font with 'for Powerline' in the name" >&2
     elif [[ "$TERM_PROGRAM" == "iTerm.app" ]]; then
       echo "For glyph support, please:
   Select iTerm2 > Preferences > Profiles > Text > Font > \
 Select font with 'for Powerline' in the name" >&2
     fi
 
   elif command -v fc-cache ; then
       # Reset font cache on Linux
       echo "Resetting font cache, this may take a moment..." >&2
       fc-cache -f "$font_dir"
   fi
 fi
 
 # shellcheck source=/dev/null
 source "${powerline_root:-.}/share/bash/powerline.sh"