1 files changed, 25 insertions, 0 deletions
diff --git a/check-installed-shebang b/check-installed-shebang
new file mode 100755
index 0000000..70bc76e
--- /dev/null
+++ b/check-installed-shebang
@@ -0,0 +1,25 @@
+#!/bin/sh
+set -e
+for f; do
+	test -r "$f"
+	shebang="$(sed 1q < "$f" | \
+	           tr '\t' ' ' | \
+	           sed -n 's/#! *\([^ ]\+\)\(\| \+.*\)$/\1\n\2/p' | \
+	           sed 's/^ *//')"
+	test -n "$shebang"
+	path="$(printf '%s\n' "$shebang" | sed -n 1p)"
+	program="$(printf '%s\n' "$path" | sed 's/^.*\/\([^/]\+\)$/\1/')"
+	arguments="$(printf '%s\n' "$shebang" | sed -n 2p)"
+	argument1="$(printf '%s\n' "$arguments" | cut -d ' ' -f 1)"
+
+	if test -z "$path"; then
+		continue
+	fi
+
+	test -x "$path"
+	if test "$program" = env; then
+		which -- "${arguments}" >/dev/null 2>/dev/null
+	elif test "$program" = shebang; then
+		which -- "${argument1}" >/dev/null 2>/dev/null
+	fi
+done