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TRUSS(1)               DragonFly General Commands Manual              TRUSS(1)

NAME
     truss -- trace system calls

SYNOPSIS
     truss [-S] [-o file] -p pid
     truss [-S] [-o file] command [args]

DESCRIPTION
     The truss utility traces the system calls called by the specified process
     or program.  Output is to the specified output file, or standard error by
     default.  It does this by stopping and restarting the process being moni-
     tored via procfs(5).

     The options are as follows:

     -S      Do not display information about signals received by the process.
             (Normally, truss displays signal as well as system call events.)

     -o file
             Print the output to the specified file instead of standard error.

     -p pid  Follow the process specified by pid instead of a new command.

     command [args]
             Execute command and trace the system calls of it.  (The -p and
             command options are mutually exclusive.)

EXAMPLES
     # Follow the system calls used in echoing "hello"
           $ truss /bin/echo hello
     # Do the same, but put the output into a file
           $ truss -o /tmp/truss.out /bin/echo hello
     # Follow an already-running process
           $ truss -p 1

SEE ALSO
     kdump(1), ktrace(1), procfs(5)

HISTORY
     The truss command was written by Sean Eric Fagan for FreeBSD.  It was
     modeled after similar commands available for System V Release 4 and
     SunOS.

DragonFly 3.5                  November 23, 1997                 DragonFly 3.5