tail head cat sleep
QR code linking to this page

Manual Pages  — ACCT


acct – execution accounting file



#include <sys/types.h>
#include <sys/acct.h>


The kernel maintains the following acct information structure for all processes. If a process terminates, and accounting is enabled, the kernel calls the acct(2) function call to prepare and append the record to the accounting file.
#define AC_COMM_LEN 16

/* * Accounting structure version 2 (current). * The first byte is always zero. * Time units are microseconds. */

struct acctv2 {         uint8_t ac_zero;               /* zero identifies new version */         uint8_t ac_version;            /* record version number */         uint16_t ac_len;                /* record length */

        char     ac_comm[AC_COMM_LEN]; /* command name */         float    ac_utime;             /* user time */         float    ac_stime;             /* system time */         float    ac_etime;             /* elapsed time */         time_t   ac_btime;             /* starting time */         uid_t    ac_uid;               /* user id */         gid_t    ac_gid;               /* group id */         float    ac_mem;               /* average memory usage */         float    ac_io;                /* count of IO blocks */         __dev_t ac_tty;               /* controlling tty */

        uint16_t ac_len2;               /* record length */         union {                 __dev_t  ac_align;     /* force v1 compatible alignment */

#define AFORK   0x01                    /* forked but not exec'ed */ /* ASU is no longer supported */ #define ASU     0x02                    /* used super-user permissions */ #define ACOMPAT 0x04                    /* used compatibility mode */ #define ACORE   0x08                    /* dumped core */ #define AXSIG   0x10                    /* killed by a signal */ #define ANVER   0x20                    /* new record version */

                uint8_t ac_flag;       /* accounting flags */         } ac_trailer;

#define ac_flagx ac_trailer.ac_flag };

If a terminated process was created by an execve(2), the name of the executed file (at most ten characters of it) is saved in the field ac_comm and its status is saved by setting one of more of the following flags in ac_flag: AFORK, ACOMPAT, ACORE and ASIG. ASU is no longer supported. ANVER is always set in the above structure.


lastcomm(1), acct(2), execve(2), sa(8)


A acct file format appeared in AT&T v7 . The current record format was introduced on May 2007. It is backwards compatible with the previous format, which is still documented in <sys/acct.h> and supported by lastcomm(1) and sa(8).

ACCT (5) May 15, 2007

tail head cat sleep
QR code linking to this page

Please direct any comments about this manual page service to Ben Bullock. Privacy policy.

If you sat a monkey down in front of a keyboard, the first thing typed would be a unix command.
— Bill Lye