lcm-logger(1)

💖 lcm-logger(1) — bestie's guide to the LCM data logger 💖

okay so this is the manual page for lcm-logger, which lives in the Lightweight Communications and Marshalling (LCM) project, and it's literally just... a data logger. iconic behavior. let's go 🫶

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✨ NAME ✨

lcm-logger — data logger 🌸

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✨ SYNOPSIS ✨

lcm-logger [options] [FILE]

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✨ DESCRIPTION ✨

so. LCM message logging utility, periodt. 💅

It subscribes to all channels on an LCM network, and it records all messages received to FILE. And if FILE isn't specified? No stress bestie, a filename gets chosen automatically for you. 🎀

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✨ OPTIONS ✨

The following options are provided by lcm-logger:

• -c, --channel=CHAN — Channel string to pass to lcm_subscribe. (default: ".*") — so by default it's grabbing literally everything, main character energy 😌
• --flush-interval=MS — Flush the log file to disk every MS milliseconds. (default: 100)
• -f, --force — Overwrite existing files. The default behavior is to fail if the output file already exists. so like, it's not being rude, it's just being careful 🙈
• -h, --help — Shows some help text and exits
• -i, --increment — Automatically append a suffix to FILE such that the resulting filename does not already exist. This option precludes -f and --rotate. (they do not vibe together, pick a lane 💀)
• -l, --lcm-url=URL — Log messages on the specified LCM URL
• -m, --max-unwritten-mb=SIZE — Maximum size of received but unwritten messages to store in memory before dropping messages. (default: 100 MB)
• --rotate=NUM — When creating a new log file, rename existing files out of the way and always write to FILE.0. If FILE.0 already exists, it is renamed to FILE.1. If FILE.1 exists, it is renamed to FILE.2, etc. If FILE.NUM exists, then it is deleted. This option precludes -i.
• --split-mb=N — Automatically start writing to a new log file once the log file exceeds N MB in size (can be fractional). This option requires -i or --rotate.
• -q, --quiet — Suppress normal output and only report errors.
• -s, --strftime — Format FILE with strftime.
• -v, --invert-channels — Invert channels. Log everything that CHAN does not match. ✨

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🔄 ROTATING AND SPLITTING 🔄

okay this part is for the long-haul girlies 🧚

For long-term logging, lcm-logger can rotate through a fixed number of log files, moving to a new log file as existing files reach a maximum size. To do this, use --rotate and --split-mb. For example:

# Rotate through logfile.0, logfile.1, ... logfile.4
lcm-logger --rotate=5 --split-mb=2 logfile

Moving to a new file happens either when the current log file size exceeds the limit specified by --split-mb, or when lcm-logger receives a SIGHUP.

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📡 SIGNALS 📡

On platforms defining SIGHUP, lcm-logger will react to HUP by closing the active log file and opening a new one. she heard the signal and she MOVED 🔥

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👀 SEE ALSO 👀

strftime(3)

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📜 COPYRIGHT 📜

lcm-logger is part of the Lightweight Communications and Marshalling (LCM) project. Permission is granted to copy, distribute and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. See the file COPYING in the LCM distribution for more details regarding distribution.

LCM is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with LCM; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

no cap, read the license. it's giving legally binding bestie 💀

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✍️ AUTHOR ✍️

This manual page was written by Albert Huang. 🫶

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aaaand that's the whole page!! this one came from the LCM project, version stamped 2009-07-28, and it's the lcm-logger(1) manual — so if you're reading this in the year of our lord 2009, hiiii. anyway go log some messages, you ate 💖🌸✨🎀🦋