[9fans] Printenv(1)

[9fans] Printenv(1)

[lucio]

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This makes it possible for me to test (and fix) ENV handling in Tcl.
Others may find it useful, I'm sure I should not have reinvented the
wheel, but it was quicker than looking up the wheel patent application
:-)

Add features to taste, I didn't even consult the Unix man pages.

++L

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#include	<u.h>
#include	<libc.h>

main (int argc, char **argv) {
	int fd, x;
	long nd;
	Dir *buf;

	USED(argc);
	USED(argv);
	fd = open ("#e", OREAD);
	nd = dirreadall (fd, &buf);

	for (x = 0; x < nd; x++) {
		print ("%s=%s\n", buf[x].name, getenv (buf[x].name));
	}
	exits (0);
	return 0;
}

Re: [9fans] Printenv(1)

[Richard Miller]

> Others may find it useful, I'm sure I should not have reinvented the
> wheel, ...

For a lazier way to get a similar result, try grep '^' /env/*

Re: [9fans] Printenv(1)

[rog]

> For something that handles lists properly,
>
> cd /env
> whatis * | grep '='

pity about the "not found" messages, problems with variables
containing newlines and other exceptions...

for more-than-casual use, i think a C tool would probably
be better, maybe something like this:

#include	<u.h>
#include	<libc.h>

void
printenv(char *name, int len)
{
	int r, f, z;
	char *ans, *t, *ep, *p;
	char *ename;

	ename = smprint("#e/%s", name);
	f = open(ename, OREAD);
	if(f < 0)
		return;

	ans = malloc(len+1);
	if(ans){
		r = read(f, ans, len);
		print("%q=", name);
		if(r >= 0){
			ep = ans + r;
			t = ans;
			z = 0;
			for(p = ans; p < ep; p++){
				if(*p == '\0'){
					print("%q ", t);
					t = p+1;
					z = 1;
				}
			}
			if(z == 0){
				*p = '\0';
				print("%q", ans);
			}
			print("\n");
		}
	}
	close(f);
	free(ans);
}

void
main(int, char **)
{
	int fd, i;
	long nd;
	Dir *buf;

	fd = open("#e", OREAD);
	nd = dirreadall(fd, &buf);
	quotefmtinstall();

	for(i = 0; i < nd; i++)
		printenv(buf[i].name, buf[i].length);
}

Re: [9fans] Printenv(1)

[Russ Cox]

It'd be even better if it printed the ( and )
so that the output was valid rc syntax.

Re: [9fans] Printenv(1)

[rog]

> It'd be even better if it printed the ( and )
> so that the output was valid rc syntax.

no sooner said than done!

#include	<u.h>
#include	<libc.h>

void
printenv(char *name, int len)
{
	int r, f, z;
	char *ans, *t, *ep, *p;
	char *ename;

	ename = smprint("#e/%s", name);
	f = open(ename, OREAD);
	if(f < 0)
		return;

	ans = malloc(len+1);
	if(ans){
		r = read(f, ans, len);
		print("%q=(", name);
		if(r >= 0){
			ep = ans + r;
			t = ans;
			z = 0;
			for(p = ans; p < ep; p++){
				if(*p == '\0'){
					print("%q ", t);
					t = p+1;
					z = 1;
				}
			}
			if(z == 0){
				*p = '\0';
				print("%q", ans);
			}
			print(")\n");
		}
	}
	close(f);
	free(ans);
}

void
main(int, char **)
{
	int fd, i;
	long nd;
	Dir *buf;

	fd = open("#e", OREAD);
	nd = dirreadall(fd, &buf);
	quotefmtinstall();

	for(i = 0; i < nd; i++)
		printenv(buf[i].name, buf[i].length);
}

Re: [9fans] Printenv(1)

[lucio]

> It'd be even better if it printed the ( and )
> so that the output was valid rc syntax.

Hey, wait a minute!  I was looking for a POSIX operation!

I was assuming that Plan 9 did not need such a thing, otherwise Bell
Labs would have provided one.

Really, now!

++L