bootlogd - record boot messages
/sbin/bootlogd [
-c] [
-d] [
-e] [
-r]
[
-s] [
-v] [
-l logfile ] [
-p pidfile ]
bootlogd runs in the background and copies all strings sent to the
/dev/console device to a logfile. If the
logfile is not
accessible, the messages will be kept in memory until it is.
- -d
- Do not fork and run in the background.
- -e
- Print escape characters to the boot log file. This turns
off filtering of escape characters and allows tools like GNU
less(1) to see and use colour control characters (show the log in
colour).
- -c
- Attempt to write to the logfile even if it does not yet
exist. Without this option, bootlogd will wait for the logfile to
appear before attempting to write to it. This behavior prevents
bootlogd from creating logfiles under mount points.
- -r
- If there is an existing logfile called logfile
rename it to logfile~ unless logfile~ already exists.
- -s
- Ensure that the data is written to the file after each line
by calling fdatasync(3). This will slow down a fsck(8)
process running in parallel.
- -v
- Show version.
-
-l logfile
- Log to this logfile. The default is
/var/log/boot.
-
-p pidfile
- Put process-id in this file. The default is no
pidfile.
bootlogd saves log data which includes control characters. The log is
technically a text file, but not very easy for humans to read. To address this
the
readbootlog(1) command can be used to display the boot log without
the control characters.
bootlogd works by redirecting the console output from the console device.
(Consequently
bootlogd requires PTY support in the kernel
configuration.) It copies that output to the real console device and to a log
file. There is no standard way of ascertaining the real console device if you
have a new-style
/dev/console device (major 5, minor 1) so
bootlogd parses the kernel command line looking for
console=...
lines and deduces the real console device from that. If that syntax is ever
changed by the kernel, or a console type is used that
bootlogd does not
know about then
bootlogd will not work.
Miquel van
Smoorenburg
dmesg(8),
fdatasync(3),
readbootlog(1)