which $1 2>&1 | perl -ne 'if (not m{^/}) { exit 1 }'
}
-# Prints the current OS. Supported are Debian (debian), Gentoo (gentoo) and
-# Mac OS X (darwin) at the moment. If an unsupported OS is used an error is
-# printed.
+# Print the current OS. The following OS are supported at the moment:
+# - Debian (debian)
+# - Gentoo (gentoo)
+# - Mac OS X (darwin)
+# If an unsupported OS is used an error is printed.
os() {
if [ -f /etc/debian_version ]; then
echo debian