who(1) who(1) NAME who - display who is on the system SYNOPSIS who [-mu] -s [-bHlprt] [ file ] who [-mTu] [-abdHlprt] [ file ] who -qn x [ file ] who am i who am I DESCRIPTION who can list the user's name, terminal line, login time, elapsed time since activity occurred on the line, and the process ID of the command interpreter (shell) for each current UNIX system user. It examines the /var/adm/utmpx file to obtain its information. If file is given, that file (which must be in utmpx(4) format, and must have the filename end with the letter x) is examined. Usually, file will be /var/adm/wtmpx, which contains a history of all the logins since the file was last created. Note that who shows only users of ttys and it does not report any logged in users who are simply running X applications from their desktop menus. OPERANDS who with the am i or am I operands identifies the invoking user. OPTIONS With options, who can list logins, logoffs, reboots, and changes to the system clock, as well as other processes spawned by the init process. These options are: -u This option lists only those users who are currently logged in. The name is the user's login name. The line is the name of the line as found in the directory /dev. The time is the time that the user logged in. The idle column contains the number of hours and minutes since activity last occurred on that particular line (roughly, the last time something was written on that line). A dot (.) indicates that the terminal has seen activity in the last minute and is therefore ``current.'' If more than twenty-four hours have elapsed or the line has not been used since boot time, the entry is marked old. This field is useful when trying to determine whether a person is working at the terminal or not. The pid is the process ID of the user's shell. The comment is the comment field associated with this line as found in /etc/inittab [see inittab(4)]. This can contain information about where the terminal is located, the telephone number of the dataset, type of terminal if hard-wired, and so on. -T This option is the same as the -u option, except that the state of the terminal line is printed. The state describes whether someone else can write to that terminal. A + appears if the terminal is writable by anyone; a - appears if it is not. root can write to all lines having a + or a - in the state field. If a bad line is encountered, a ? is printed. -l This option lists only those lines on which the system is waiting for someone to login. The name field is LOGIN in such cases. Other fields are the same as for user entries except that the state field does not exist. -m This option outputs only information about the current terminal. -H This option will print column headings above the regular output. -q This is a quick who, displaying only the names and the number of users currently logged on. When this option is used, all other options are ignored. -p This option lists any other process which is currently active and has been previously spawned by init. The name field is the name of the program executed by init as found in /etc/inittab. The state, line, and idle fields have no meaning. The comment field shows the id field of the line from /etc/inittab that spawned this process. See inittab(4). -d This option displays all processes that have expired and not been respawned by init. The exit field appears for dead processes and contains the termination and exit values [as returned by wait(2)], of the dead process. This can be useful in determining why a process terminated. -b This option indicates the time and date of the last reboot. -r This option indicates the current run-level of the init process. In addition, it produces the current state, the number of previous times the system had been in the current state, and the previous state under the idle, pid, and comment headings, respectively. -t This option indicates the last change to the system clock (via the date command) by root. See su(1M). -a This option processes /var/adm/utmpx or the named file with all options turned on. -s This option is the default and lists only the name, line, and time fields. -n x This option takes a numeric argument, x, which specifies the number of users to display per line. x must be at least 1. The -n option must be used with -q. Note to privileged users: after a shutdown to the single-user state, who returns a prompt; the reason is that since /var/adm/utmpx is updated at login time and there is no login in single-user state, who cannot report accurately on this state. who am i, however, returns the correct information. ENVIRONMENT VARIABLES The following environment variables affect the execution of who: LANG provide a default value for the internationalization variables that are unset or null. If LANG is unset or null the corresponding value from the implementation-specific default locale will be used. If any of the internationalization variables contains an invalid setting, the utility will behave as if none of the variables had been defined. LC_ALL if set to a non-empty string value, override the values of all the other internationalization variables. LC_CTYPE determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single - as opposed to multi- byte - characters in arguments). LC_MESSAGES determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error. NLSPATH determine the location of message catalogs for the processing of LC_MESSAGES. STDOUT The general format for output is: name [state] line time [idle] [pid] [comment] [exit] The name, line, and time information is produced by all options except -q; the state information is produced only by -T; the idle and pid information is produced only by -u, -l, and -T; and the comment and exit information is produced only by -a. The information produced for -p, -d, and -r is explained during the discussion of each option. The following format is used for the -T option: "%s %c %s %s\n", <name>, <terminal state>, <terminal name>, <time of login> where <terminal state> is one of the following characters: + the terminal allows write access to other users - the terminal denies write access to other users ? the terminal write-access state cannot be determined EXIT STATUS The following exit values are returned: 0 successful completion >0 an error occurred NOTES w(1) and who(1) can report different idle times for the same line. w will report the time elapsed since input occurred, while who will report the time elapsed since output occurred (roughly speaking). If there is a job running that produces output, the idle times will differ between the two programs: babylon: who -Hu NAME LINE TIME IDLE PID COMMENTS root ttyd1 Jul 6 10:37 . 1955 alt console babylon: w User tty from login@ idle JCPU PCPU what root d1 10:37am 5:54 23 23 tail -f SYSLOG FILES /var/adm/wtmpx /etc/inittab /var/adm/utmpx /usr/lib/locale/locale/LC_MESSAGES/uxcore.abi /usr/lib/locale/locale/LC_MESSAGES/uxsgicore language-specific message file [See LANG on environ (5).] SEE ALSO date(1), login(1), mesg(1), su(1M), init(1M), inittab(4), utmpx(4), wait(2) Page 4