TRUSS(1) BSD General Commands Manual TRUSS(1)NAMEtruss — trace system calls
SYNOPSIStruss [-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 ALSOkdump(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.
BSD November 23, 1997 BSD
