View information about your user on a Linux system
The groups command displays the list of groups that your user is a member of.
[neo@deusexmachina]:~> groups neo cdrom floppy audio dip video plugdev bluetooth scanner netdev |
Using the id command will display a more verbose output that shows the uid and name of the currently logged in user, the current group that the user is joined to at the moment and the other groups that the user is a member of.
[neo@deusexmachina]:~> id uid=1000(neo) gid=1000(neo) groups=1000(neo),24(cdrom),25(floppy),29(audio),30(dip),44(video),46(plugdev),106(bluetooth),108(scanner),110(netdev) |
This is my /etc/group file. The syntax is very simple. It has: Group Name : GID : username1,username2,username3,. Adding a new group is easy with either the groupadd command or by editing the /etc/group file directly. You must ensure that you use a unique GID for your new group and that it is a higher number than other GID numbers already in use.
root:x:0: daemon:x:1: bin:x:2: sys:x:3: adm:x:4: tty:x:5: disk:x:6: lp:x:7: mail:x:8: news:x:9: uucp:x:10: man:x:12: proxy:x:13: kmem:x:15: dialout:x:20: fax:x:21: voice:x:22: cdrom:x:24:neo floppy:x:25:neo tape:x:26: sudo:x:27: audio:x:29:neo,pulse,timidity dip:x:30:neo www-data:x:33: backup:x:34: operator:x:37: list:x:38: irc:x:39: src:x:40: gnats:x:41: shadow:x:42: utmp:x:43: video:x:44:neo sasl:x:45: plugdev:x:46:neo staff:x:50: games:x:60: users:x:100: nogroup:x:65534: libuuid:x:101: crontab:x:102: Debian-exim:x:103: mlocate:x:104: messagebus:x:105: bluetooth:x:106:neo fuse:x:107: scanner:x:108:saned,neo utempter:x:109: netdev:x:110:neo saned:x:111: ssl-cert:x:112: neo:x:1000: gordon:x:1001: gdm:x:113: colord:x:114: pulse:x:115: pulse-access:x:116: rtkit:x:117: lightdm:x:118: ssh:x:119: timidity:x:120: lpadmin:x:121: avahi:x:122: zeroinst:x:123: ntp:x:124: vboxusers:x:125: |
The finger command may also be used to view information about your user very quickly.
[neo@deusexmachina]:~> finger -lmps Login: neo Name: John Cartwright Directory: /home/neo Shell: /bin/tcsh On since Sun May 6 18:59 (EST) on pts/0 from :0.0 New mail received Sun May 6 12:27 2012 (EST) Unread since Thu Apr 19 19:58 2012 (EST) [neo@deusexmachina]:~> |
These two commands are also useful, the former maybe more than the latter.
[neo@deusexmachina]:~> w 19:21:12 up 1 day, 23:03, 1 user, load average: 0.00, 0.02, 0.05 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT neo pts/0 :0.0 18:59 0.00s 0.03s 0.00s w [neo@deusexmachina]:~> who am i neo pts/0 May 6 18:59 (:0.0) [neo@deusexmachina]:~> |