Only match #!/bin/bash in scripts

Our dib-lint checking is only considering scripts with #!/bin/bash.
While there's nothing really wrong with some other shebang line like
"#!/usr/bin/env bash" let's keep things consistent.

We can use the same regex match to reduce a few forks in the main
checking.

Also a minor cleanup to the file matching

Change-Id: I609721b2671e704ea26075dad7e5b39a8b858f6b

bin/dib-lint

@@ -63,12 +63,15 @@ TMPDIR=$(mktemp -d /tmp/tmp.XXXXXXXXXX)
 trap "rm -rf $TMPDIR" EXIT
 for i in $(find elements -type f   \
                 -not -name \*~     \
+                -not -name \#\*\#  \
                 -not -name \*.orig \
                 -not -name \*.rst  \
                 -not -name \*.yaml \
                 -not -name \*.py   \
                 -not -name \*.pyc); do
+
     exclusions=("$(parse_exclusions $i)")
+
     # Check that files starting with a shebang are +x
     firstline=$(head -n 1 "$i")
     if [ "${firstline:0:2}" = "#!" ]; then
@@ -77,7 +80,6 @@ for i in $(find elements -type f \
         fi
 
         # Ensure 4 spaces indent are used
-
         if [ "$(file -b --mime-type $i)" = "text/x-python" ]; then
             flake8 $i
         else
@@ -104,6 +106,14 @@ for i in $(find elements -type f \
         fi
     fi
 
+    # for consistency, let's just use #!/bin/bash everywhere (not
+    # /usr/bin/env, etc)
+    regex='^#!.*bash'
+    if [[ "$firstline" =~ $regex &&
+                "$firstline" != "#!/bin/bash" ]]; then
+        error "$i : only use #!/bin/bash for scripts"
+    fi
+
     # Check that all scripts are set -eu -o pipefail and look for
     # DIB_DEBUG_TRACE
     # NOTE(bnemec): This doesn't verify that the set call occurs high
@@ -114,7 +124,7 @@ for i in $(find elements -type f \
     # explicitly require bash for any scripts that don't have a specific
     # need to run under other shells, and any exceptions to that rule
     # may not want these checks either.
-    if [ -n "$(echo $firstline | grep '#!/bin/bash')" ]; then
+    if [[ "$firstline" =~ '#!/bin/bash' ]]; then
         if ! excluded sete; then
             if [ -z "$(grep "^set -[^ ]*e" $i)" ]; then
                 error "$i is not set -e"

elements/gentoo/bin/install-packages

@@ -1,4 +1,4 @@
-#!/usr/bin/env bash
+#!/bin/bash
 
 # Copyright 2016 Matthew Thode
 #

elements/gentoo/root.d/10-gentoo-image

@@ -1,4 +1,5 @@
-#!/usr/bin/env bash
+#!/bin/bash
+
 # Copyright 2016 Matthew Thode
 # All Rights Reserved.
 #