---
name: "ts"
section: "1"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["linux", "freebsd", "openbsd"]
url: "https://new.carta.tech/ts"
---

# ts(1)

timestamp input

## NAME

**ts** – timestamp input

## SYNOPSIS

**ts** \[**-i** \| **-s**\] \[**-m**\] \[*format*\]

## DESCRIPTION

The **ts** utility prepends a timestamp to each line of standard input and writes it to standard output.

The options are as follows:

- **-i**

  Display time elapsed since the last timestamp.

- **-m**

  Display timestamps derived from a strictly linearly increasing clock. Without **-m**, timestamps reflect the current date and time, including time jumps if the system time is changed.

- **-s**

  Display time elapsed since the start of the program.

The optional *format* argument controls how the timestamp is displayed, according to the conversion specifications described in the [strftime(3)](/strftime/3.md) manual page. The default format is "%b %d %H:%M:%S"; or "%H:%M:%S" if one of the **-i** or **-s** options is used.

Some additional conversion specifications are also supported to append microsecond resolution: **%.S**, **%.s**, and **%.T**; which are similar to **%S**, **%s**, and **%T**. Examples: "10.00001", "1656427781.00001", and "4:20:00.00001".

## EXAMPLES

```
$ (echo foo; sleep 2; echo bar) | ts
Jun 28 12:13:38 foo
Jun 28 12:13:40 bar
$ ls | ts -i %.S
00.000452 CVS
00.000595 Makefile
00.000004 ts.1
00.000004 ts.c
```

## SEE ALSO

[strftime(3)](/strftime/3.md)

## HISTORY

A **ts** utility first appeared in the moreutils collection by Joey Hess, and was rewritten from scratch for OpenBSD 7.2.

## AUTHORS

This **ts** utility was written by Job Snijders ⟨*job@openbsd.org*⟩ and Claudio Jeker ⟨*claudio@openbsd.org*⟩.