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.
