printf does not support \e (the escape character) #910
Description
The "\e" escape sequence is recognised by at least bash versions of echo & printf, GNU coreutils /usr/bin/{echo,printf} and the GNU C compiler.
Now that printf suddenly became a builtin, it's important to not break people's scripts, or just not be worse than people are used to. Besides, the fish version of echo supports it!
I don't think "\e" is posix (dash and busybox don't support it), but when GNU standards deviate from posix, it's usually for a reason.
A patch that works for me:
diff --git a/builtin_printf.cpp b/builtin_printf.cpp
index e164f81..d5cf9e0 100644
--- a/builtin_printf.cpp
+++ b/builtin_printf.cpp
@@ -26,6 +26,7 @@
\a = alert (bell)
\b = backspace
\c = produce no further output
+ \e = escape
\f = form feed
\n = new line
\r = carriage return
@@ -319,6 +320,9 @@ void builtin_printf_state_t::print_esc_char(wchar_t c)
case L'c': /* Cancel the rest of the output. */
this->early_exit = true;
break;
+ case L'e': /* Escape. */
+ this->append_output(L'\e');
+ break;
case L'f': /* Form feed. */
this->append_output(L'\f');
break;
@@ -369,7 +373,7 @@ long builtin_printf_state_t::print_esc(const wchar_t *escstart, bool octal_0)
esc_value = esc_value * 8 + octal_to_bin(*p);
this->append_format_output(L"%c", esc_value);
}
- else if (*p && wcschr(L"\"\\abcfnrtv", *p))
+ else if (*p && wcschr(L"\"\\abcefnrtv", *p))
print_esc_char(*p++);
else if (*p == L'u' || *p == L'U')
{(There shall be 3 tabs between case labels and comments, looks like they became spaces)