aboutsummaryrefslogtreecommitdiff
path: root/toys/posix/echo.c
diff options
context:
space:
mode:
Diffstat (limited to 'toys/posix/echo.c')
-rw-r--r--toys/posix/echo.c97
1 files changed, 97 insertions, 0 deletions
diff --git a/toys/posix/echo.c b/toys/posix/echo.c
new file mode 100644
index 00000000..6fb9e43d
--- /dev/null
+++ b/toys/posix/echo.c
@@ -0,0 +1,97 @@
+/* vi: set sw=4 ts=4:
+ *
+ * echo.c - echo supporting -n and -e.
+ *
+ * Copyright 2007 Rob Landley <rob@landley.net>
+ *
+ * See http://www.opengroup.org/onlinepubs/009695399/utilities/echo.html
+
+USE_ECHO(NEWTOY(echo, "^?en", TOYFLAG_BIN))
+
+config ECHO
+ bool "echo"
+ default y
+ help
+ usage: echo [-ne] [args...]
+
+ Write each argument to stdout, with one space between each, followed
+ by a newline.
+
+ -n No trailing newline.
+ -e Process the following escape sequences:
+ \\ backslash
+ \0NNN octal values (1 to 3 digits)
+ \a alert (beep/flash)
+ \b backspace
+ \c stop output here (avoids trailing newline)
+ \f form feed
+ \n newline
+ \r carriage return
+ \t horizontal tab
+ \v vertical tab
+ \xHH hexadecimal values (1 to 2 digits)
+*/
+
+#define THIS echo
+#include "toys.h"
+
+#define FLAG_e (1<<1)
+#define FLAG_n (1<<0)
+
+void echo_main(void)
+{
+ int i = 0, out;
+ char *arg, *from = "\\abfnrtv", *to = "\\\a\b\f\n\r\t\v", *c;
+
+ for (;;) {
+ arg = toys.optargs[i];
+ if (!arg) break;
+ if (i++) xputc(' ');
+
+ // Should we output arg verbatim?
+
+ if (!(toys.optflags&FLAG_e)) {
+ xprintf("%s", arg);
+ continue;
+ }
+
+ // Handle -e
+
+ for (c=arg;;) {
+ if (!(out = *(c++))) break;
+
+ // handle \escapes
+ if (out == '\\' && *c) {
+ int n = 0, slash = *(c++);
+ char *found = strchr(from, slash);
+ if (found) out = to[found-from];
+ else if (slash == 'c') goto done;
+ else if (slash == '0') {
+ out = 0;
+ while (*c>='0' && *c<='7' && n++<3)
+ out = (out*8)+*(c++)-'0';
+ } else if (slash == 'x') {
+ out = 0;
+ while (n++<2) {
+ if (*c>='0' && *c<='9')
+ out = (out*16)+*(c++)-'0';
+ else {
+ int temp = tolower(*c);
+ if (temp>='a' && temp<='f') {
+ out = (out*16)+temp-'a'+10;
+ c++;
+ } else break;
+ }
+ }
+ // Slash in front of unknown character, print literal.
+ } else c--;
+ }
+ xputc(out);
+ }
+ }
+
+ // Output "\n" if no -n
+ if (!(toys.optflags&FLAG_n)) xputc('\n');
+done:
+ xflush();
+}