opensnoop(8) | System Manager's Manual | opensnoop(8) |
opensnoop - Trace open() syscalls. Uses Linux eBPF/bcc.
opensnoop [-h] [-T] [-x] [-p PID] [-t TID] [-d DURATION] [-n name]
opensnoop traces the open() syscall, showing which processes are attempting to open which files. This can be useful for determining the location of config and log files, or for troubleshooting applications that are failing, specially on startup.
This works by tracing the kernel sys_open() function using dynamic tracing, and will need updating to match any changes to this function.
This makes use of a Linux 4.5 feature (bpf_perf_event_output()); for kernels older than 4.5, see the version under tools/old, which uses an older mechanism.
Since this uses BPF, only the root user can use this tool.
CONFIG_BPF and bcc.
This traces the kernel open function and prints output for each event. As the rate of this is generally expected to be low (< 1000/s), the overhead is also expected to be negligible. If you have an application that is calling a high rate of open()s, then test and understand overhead before use.
This is from bcc.
Also look in the bcc distribution for a companion _examples.txt file containing example usage, output, and commentary for this tool.
Linux
Unstable - in development.
Brendan Gregg
2015-08-18 | USER COMMANDS |