From: Pietro Gagliardi <pietro10@mac.com>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
Subject: Re: [9fans] bug in echo?
Date: Wed, 26 Mar 2008 14:58:26 -0400 [thread overview]
Message-ID: <F5B1C672-6402-4073-8E19-3D5539ACB95A@mac.com> (raw)
In-Reply-To: <2dccf442569c12a4ba9193abb0392726@quanstro.net>
Is there a valid reason to have echo process the arguments given?
It's a simple mod:
#include <u.h>
#include <libc.h>
/* echo: echo args */
void
main(int argc, char *argv[])
{
int nl = 1;
ARGBEGIN{
'n':
nl = 0;
break;
default:
fprint(2, "usage: echo [-n] stuff\n");
sysfatal("usage");
}ARGEND;
for(i = 1; i < argc - 1; i++)
print("%s ", argv[i]);
print("%s%s", argv[argc - 1], nl ? "\n" : "");
exits(0);
}
However, Plan 9 has gone for years and people have not had this
problem. (Then again, so did TUPE for Unix).
Can we stick with
echo -n '-n
'
as Rob (the coauthor of that book, mind you, so he knows EXACTLY what
he is saying) said? It defies the need for handing a single argument.
If we start supporting arguments, we can have other arguments:
-e Use escape sequences.
-E Use no escape sequences.
-l (ell) One per line.
-t Separate with tabs.
-Nn Use n spaces (default 1).
-L If -l is given, use line numbers.
-o Output each character in octal.
-x Output each character in hex.
-v Make non-printing characters visible.
-r The first argument is a regular expression. Print each string
given as an argument that matches this regular expression.
and no doubt people will want them. Is this necessary? echo -e is
considered harmful (and when I started /bin/sh programming, I didn't
like that it wasn't default. Oh well).
The lesson?
echo -n '-n
'
is the solution.
next prev parent reply other threads:[~2008-03-26 18:58 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-26 11:41 Gorka Guardiola
2008-03-26 12:27 ` Rob Pike
2008-03-26 12:41 ` Gorka Guardiola
2008-03-26 12:52 ` Sape Mullender
2008-03-26 13:19 ` Gorka Guardiola
2008-03-26 20:27 ` Iruata Souza
2008-03-26 12:40 ` Anthony Martin
2008-03-26 13:13 ` Gorka Guardiola
2008-03-26 13:19 ` Joel C. Salomon
2008-03-26 13:40 ` Gorka Guardiola
2008-03-31 8:58 ` Douglas A. Gwyn
2008-03-26 13:55 ` erik quanstrom
2008-03-26 15:52 ` Gorka Guardiola
2008-03-26 17:26 ` roger peppe
2008-03-26 18:10 ` erik quanstrom
2008-03-26 18:58 ` Pietro Gagliardi [this message]
2008-03-26 19:38 ` Joel C. Salomon
2008-03-26 19:43 ` Francisco J Ballesteros
2008-03-26 20:01 ` Pietro Gagliardi
2008-03-26 20:09 ` andrey mirtchovski
2008-03-26 20:22 ` Pietro Gagliardi
2008-03-26 20:30 ` andrey mirtchovski
2008-03-26 20:56 ` Pietro Gagliardi
2008-03-26 22:06 ` Iruata Souza
2008-03-26 22:26 ` Pietro Gagliardi
2008-03-26 22:54 ` Iruata Souza
2008-03-27 3:40 ` Robert William Fuller
2008-03-27 3:47 ` Bruce Ellis
2008-04-01 9:07 ` Douglas A. Gwyn
2008-03-27 1:57 ` Gorka Guardiola
2008-03-27 2:17 ` Gorka Guardiola
2008-03-27 2:21 ` Joel C. Salomon
2008-03-27 2:37 ` Pietro Gagliardi
2008-03-27 3:45 ` Bruce Ellis
2008-03-27 16:37 ` john
2008-03-27 17:03 ` [9fans] databases erik quanstrom
2008-03-27 19:08 ` Pietro Gagliardi
2008-03-28 4:05 ` a
2008-03-28 3:46 ` [9fans] bug in echo? a
2008-03-31 16:26 ` Russ Cox
2008-04-01 9:07 ` Douglas A. Gwyn
2008-03-26 20:10 ` roger peppe
2008-04-01 9:06 ` Douglas A. Gwyn
2008-04-01 9:06 ` Douglas A. Gwyn
2008-04-01 9:22 ` Anders Li
2008-04-03 8:54 ` Douglas A. Gwyn
2008-04-03 16:46 ` ron minnich
2008-04-03 18:04 ` Gorka Guardiola
2008-04-03 18:23 ` Martin Neubauer
2008-04-03 19:11 ` Pietro Gagliardi
2008-04-03 19:30 ` Steven D. Vormwald
2008-04-03 19:44 ` Pietro Gagliardi
2008-04-03 22:16 ` a
2008-04-03 22:26 ` Pietro Gagliardi
2008-04-03 22:44 ` John Floren
2008-04-03 22:53 ` Pietro Gagliardi
2008-04-03 23:12 ` Martin Neubauer
2008-04-08 23:51 ` david parsons
2008-04-09 0:02 ` Pietro Gagliardi
2008-03-26 13:15 ` Joel C. Salomon
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