Add linting code for detecting shebang bashisms.

This will prevent regressions in OpenBSD compatibility, since OpenBSD
doesn't support passing arguments in the #! line.

tools/lint-all

@@ -76,6 +76,8 @@ for filepath in files:
 
     by_lang[exn].append(filepath)
 
+by_lang['.sh'] = filter(None, map(str.strip, subprocess.check_output("grep --files-with-matches '#!.*\(ba\)\?sh' $(find scripts/ tools/ bin/ -type f | grep -v [.])", shell=True).split('\n')))
+
 # Invoke the appropriate lint checker for each language,
 # and also check files for extra whitespace.
 
@@ -169,6 +171,10 @@ python_rules = [
 python_line_skip_rules = [
     '\s*[*#]', # comments
     ]
+bash_rules = [
+    {'pattern': '#!.*sh [-xe]',
+     'description': 'Fix shebang line with proper call to /usr/bin/env for Bash path, change -x|-e switches to set -x|set -e'},
+    ]
 
 def check_custom_checks():
     failed = False
@@ -181,6 +187,10 @@ def check_custom_checks():
         if custom_check_file(fn, js_rules):
             failed = True
 
+    for fn in by_lang['.sh']:
+        if custom_check_file(fn, bash_rules):
+            failed = True
+
     return failed
 
 lint_functions = {}