---
name: "trace-cmd-show"
section: "1"
platform: "linux"
package: "trace-cmd"
version: "3.4-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/trace-cmd-show"
---

# trace-cmd-show(1)

show the contents of the Ftrace Linux kernel tracing buffer.

## NAME

trace-cmd-show - show the contents of the Ftrace Linux kernel tracing buffer.

## SYNOPSIS

**trace-cmd show** \[*OPTIONS*\]

## DESCRIPTION

The [trace-cmd(1)](/trace-cmd/1.md) show displays the contents of one of the Ftrace Linux kernel tracing files: trace, snapshot, or trace\_pipe. It is basically the equivalent of doing:

```
cat /sys/kernel/debug/tracing/trace
```

## OPTIONS

- **-p**

  Instead of displaying the contents of the "trace" file, use the "trace\_pipe" file. The difference between the two is that the "trace" file is static. That is, if tracing is stopped, the "trace" file will show the same contents each time.

  ```
  The "trace_pipe" file is a consuming read, where a read of the file
  will consume the output of what was read and it will not read the
  same thing a second time even if tracing is stopped. This file
  als will block. If no data is available, trace-cmd show will stop
  and wait for data to appear.
  ```

- **-s**

  Instead of reading the "trace" file, read the snapshot file. The snapshot is made by an application writing into it and the kernel will perform as swap between the currently active buffer and the current snapshot buffer. If no more swaps are made, the snapshot will remain static. This is not a consuming read.

- **-c** *cpu*

  Read only the trace file for a specified CPU.

- **-f**

  Display the full path name of the file that is being displayed.

- **-B** *buf*

  If a buffer instance was created, then the **-B** option will access the files associated with the given buffer.

- **--tracing\_on**

  Show if tracing is on for the given instance.

- **--current\_tracer**

  Show what the current tracer is.

- **--buffer\_size**

  Show the current buffer size (per-cpu)

- **--buffer\_total\_size**

  Show the total size of all buffers.

- **--buffer\_subbuf\_size**

  Show the size in kilobytes of the sub-buffers of the ring buffer. The ring buffer is broken up into equal size sub-buffers were an event can only be as big as the sub-buffer data section (the size minus its meta data).

- **--buffer\_percent**

  Show the percentage the buffer must be filled before a reader that is blocked on the trace\_pipe\_raw file will be woken up.

  ```
  0       : wake up immediately on any new data
  1 - 99  : wake up on this percentage of the sub-buffers being full
  100     : wake up after the buffer is full and the writer is on the last sub-buffer
  ```

- **--ftrace\_filter**

  Show what function filters are set.

- **--ftrace\_notrace**

  Show what function disabled filters are set.

- **--ftrace\_pid**

  Show the PIDs the function tracer is limited to (if any).

- **--graph\_function**

  Show the functions that will be graphed.

- **--graph\_notrace**

  Show the functions that will not be graphed.

- **--hist** *\[system:\]event*

  Show the content of a histogram "hist" file for a given event

- **--trigger** *\[system:\]event*

  Show the content of the "trigger" file for a given event

- **--cpumask**

  Show the mask of CPUs that tracing will trace.

## SEE ALSO

[trace-cmd(1)](/trace-cmd/1.md), [trace-cmd-record(1)](/trace-cmd-record/1.md), [trace-cmd-report(1)](/trace-cmd-report/1.md), [trace-cmd-start(1)](/trace-cmd-start/1.md), [trace-cmd-extract(1)](/trace-cmd-extract/1.md), [trace-cmd-reset(1)](/trace-cmd-reset/1.md), [trace-cmd-split(1)](/trace-cmd-split/1.md), [trace-cmd-list(1)](/trace-cmd-list/1.md), [trace-cmd-listen(1)](/trace-cmd-listen/1.md)

## AUTHOR

Written by Steven Rostedt, \<**rostedt@goodmis.org**\[1\]\>

## RESOURCES

**https://git.kernel.org/pub/scm/utils/trace-cmd/trace-cmd.git/**

## COPYING

Copyright (C) 2010 Red Hat, Inc. Free use of this software is granted under the terms of the GNU Public License (GPL).

## NOTES

- 1\.

  rostedt@goodmis.org

  mailto:rostedt@goodmis.org