username / id
Hi all, Is there any function to get the user name if uid is known, and vice versa ? Similar for group. Thanks, Vu ___ Linux-users mailing list [EMAIL PROTECTED] Unsubscribe/Suspend/Etc - http://smtp.linux-sxs.org/mailman/listinfo/linux-users
Re: username / id
Vu Pham wrote:
Hi all,
Is there any function to get the user name if uid is known, and vice versa ?
Similar for group.
Thanks,
cat /etc/passwd | grep ^.*:x:500: | awk -F: '{print $1}'
cat /etc/passwd | grep ^.*:x:[0-9]*:500 | awk -F: '{print $1}'
This is probably not what you want but it does return a name from uid or
gid...
--
James McDonald
Singleton Australia
61+ (0)2 65712401
61+ 0428 320 219
If you stand on your head, you will get footprints in your hair.
Linux 2.6.0-james2 #3 Wed Oct 29 10:25:46 EST 2003 athlon i386 GNU/Linux
22:50:00 up 1 day, 10:54, 2 users, load average: 0.07, 0.24, 0.44
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Re: username / id
- Original Message -
From: James McDonald [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Thursday, October 30, 2003 5:57 AM
Subject: Re: username / id
Vu Pham wrote:
Hi all,
Is there any function to get the user name if uid is known, and vice
versa ?
Similar for group.
Thanks,
cat /etc/passwd | grep ^.*:x:500: | awk -F: '{print $1}'
cat /etc/passwd | grep ^.*:x:[0-9]*:500 | awk -F: '{print $1}'
This is probably not what you want but it does return a name from uid or
gid...
Oh, that works. I would like to know if there is an API so that I can use it
in my C app, or do I need to run some commands like your suggestion and
capture the output.
Thanks, James.
Vu
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Re: username / id
This may help if you are doing this from a program: man getuid On Thu, 30 Oct 2003 22:57:14 +1100 James McDonald [EMAIL PROTECTED] wrote: Vu Pham wrote: Hi all, Is there any function to get the user name if uid is known, and vice versa ? Similar for group. -- ++···+ · Roger Oberholtzer · E-mail: [EMAIL PROTECTED]· · OPQ Systems AB · WWW: http://www.opq.se/ · · Erik Dahlbergsgatan 41-43 ·Phone: Int + 46 8 314223 · · 115 34 Stockholm · Mobile: Int + 46 733 621657 · · Sweden · Fax: Int + 46 8 302602 · ++···+ ___ Linux-users mailing list [EMAIL PROTECTED] Unsubscribe/Suspend/Etc - http://smtp.linux-sxs.org/mailman/listinfo/linux-users
Re: username / id
On Thu, 30 Oct 2003 06:25:39 -0600
Vu Pham [EMAIL PROTECTED] wrote:
- Original Message -
From: James McDonald [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Thursday, October 30, 2003 5:57 AM
Subject: Re: username / id
Vu Pham wrote:
Hi all,
Is there any function to get the user name if uid is known, and vice
versa ?
Similar for group.
Thanks,
cat /etc/passwd | grep ^.*:x:500: | awk -F: '{print $1}'
cat /etc/passwd | grep ^.*:x:[0-9]*:500 | awk -F: '{print $1}'
This is probably not what you want but it does return a name from uid or
gid...
Oh, that works. I would like to know if there is an API so that I can use
it in my C app, or do I need to run some commands like your suggestion and
capture the output.
The closest to a C function I have seen is only for the current user:
getlogin or cuserid. For other users, I do not know. These functions use the
'utmp' function to get their information, and not /etc/passwd.
So, if you are interested in currently logged in users, you can use the
utmp() function. Otherwise, fopen(/etc/passwd, ...)/fread() is the way to
go.
--
++···+
· Roger Oberholtzer · E-mail: [EMAIL PROTECTED]·
· OPQ Systems AB · WWW: http://www.opq.se/ ·
· Erik Dahlbergsgatan 41-43 ·Phone: Int + 46 8 314223 ·
· 115 34 Stockholm · Mobile: Int + 46 733 621657 ·
· Sweden · Fax: Int + 46 8 302602 ·
++···+
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Re: username / id
Thanks everybody who has replied. Perhaps I will go with one of the following suggestions : - popen with the cat /etc/passwd | grep or - read the /etc/passwd , /etc/group and parse them. Thanks ! Vu ___ Linux-users mailing list [EMAIL PROTECTED] Unsubscribe/Suspend/Etc - http://smtp.linux-sxs.org/mailman/listinfo/linux-users
Re: username / id
On Thu, 30 Oct 2003 07:53:35 -0600
Rick Sivernell [EMAIL PROTECTED] wrote:
On Thu, 30 Oct 2003 06:25:39 -0600
Vu Pham [EMAIL PROTECTED] wrote:
- Original Message -
From: James McDonald [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Thursday, October 30, 2003 5:57 AM
Subject: Re: username / id
Vu Pham wrote:
Hi all,
Is there any function to get the user name if uid is known, and vice
versa ?
Similar for group.
Thanks,
cat /etc/passwd | grep ^.*:x:500: | awk -F: '{print $1}'
cat /etc/passwd | grep ^.*:x:[0-9]*:500 | awk -F: '{print $1}'
This is probably not what you want but it does return a name from uid
or gid...
Oh, that works. I would like to know if there is an API so that I can
use it in my C app, or do I need to run some commands like your
suggestion and capture the output.
Thanks, James.
Vu
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Vu
use exec and put the cat in a string. the exec will execute this
from
code.
It really is not necessary to program via exec to read a file. Try the
attached code.
Put it in /tmp. Compile with 'make qq', Run as ./qq
--
++···+
· Roger Oberholtzer · E-mail: [EMAIL PROTECTED]·
· OPQ Systems AB · WWW: http://www.opq.se/ ·
· Erik Dahlbergsgatan 41-43 ·Phone: Int + 46 8 314223 ·
· 115 34 Stockholm · Mobile: Int + 46 733 621657 ·
· Sweden · Fax: Int + 46 8 302602 ·
++···+
#include stdio.h
char *myGetUserName(int target) {
FILE *pwdfile;
static char name[80];
if (!(pwdfile = fopen(/etc/passwd, r))) return(0);
while (1) {
char aline[256];
int uid;
if (!fgets(aline, 200, pwdfile)) { name[0] = 0; break; }
sscanf(aline, %*[^:]: // login (skip)
%*[^:]: // group (skip)
%d: // uid
%*d: // gid (skip)
%[^:],// name
uid, name);
if (uid == target) break;
}
fclose(pwdfile);
return(name);
}
main ()
{
printf(uid 500 is %s\n, myGetUserName(500));
printf(uid 200 is %s\n, myGetUserName(200));
}
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Re: username / id
vu pham wrote: Thanks everybody who has replied. Perhaps I will go with one of the following suggestions : - popen with the cat /etc/passwd | grep or - read the /etc/passwd , /etc/group and parse them. Thanks ! Vu Umm I was just playing with id and if you [EMAIL PROTECTED] tmp]$ id apache uid=48(apache) gid=48(apache) groups=48(apache) [EMAIL PROTECTED] tmp]$ id apache -u 48 [EMAIL PROTECTED] tmp]$ id apache -g 48 [EMAIL PROTECTED] tmp]$ id apache -gu id: cannot print only user and only grou So forget about my earlier suggestion of cat'ing /etc/password and just use id if you are trying to use the local uid then [EMAIL PROTECTED] tmp]$ whoami | id uid=500(james) gid=500(james) groups=500(james),10(wheel) Well at least we aren't limited for choice using *nix -- James McDonald Singleton Australia 61+ (0)2 65712401 61+ 0428 320 219 Creativity is no substitute for knowing what you are doing. Linux 2.6.0-james3 #4 Thu Oct 30 23:46:04 EST 2003 athlon i386 GNU/Linux 06:40:00 up 6:08, 3 users, load average: 0.44, 0.65, 0.44 ___ Linux-users mailing list [EMAIL PROTECTED] Unsubscribe/Suspend/Etc - http://smtp.linux-sxs.org/mailman/listinfo/linux-users
Re: username / id
Roger That too will do the trick, my suggestion was using the cl stuff offered only. cheers -- Rick Sivernell Dallas, Texas 75287 972 306-2296 [EMAIL PROTECTED] Gentoo Linux Registered Linux User .~. / v \ /( _ )\ ^ ^ In Linux we trust! ___ Linux-users mailing list [EMAIL PROTECTED] Unsubscribe/Suspend/Etc - http://smtp.linux-sxs.org/mailman/listinfo/linux-users
