flasher/flasher.1 at master · murrayn/flasher · GitHub

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.\" flasher - Copyright (C) 2002 Murray Nesbitt (websrc@nesbitt.ca)
.\"
.\" This program is protected and licensed under the following terms and
.\" conditions: 1) it may not be redistributed in binary form without the
.\" explicit permission of the author; 2) when redistributed in source
.\" form, in whole or in part, this complete copyright statement must
.\" remain intact.
.TH FLASHER 1
.SH NAME
flasher \-   flash keyboard LEDs to indicate file writes
.SH SYNOPSIS
.B flasher
[
.B -u seconds
]
[
.B -k /dev/ttyXX
]
.B -{c|n|s} file1:file2:...:fileN
.SH DESCRIPTION
.I  flasher
monitors changes to one or more files, and indicates the number of writes
to these files by briefly flashing a console LED once for each write.
The flashing sequence is repeated, after a brief pause, until the files
have been read.  As the files are subsequently read, the number of LED
flashes is reduced.  When all monitored files have been read, the console
LED will be disabled.
.PP
The most obvious use is to monitor specific system log or mail files.
.PP
Multiple LEDs can be used. Each possible LED (-c, -n or -s) takes a list
of colon-separated file arguments.  For example, when invoked as:
.PP
.RS
# flasher -s /var/log/messages:/var/mail/root
.RE
.PP
the Scroll Lock LED will flash once for each write made to either of these
files, until the files are read.  When /var/log/messages has been read,
the Scroll Lock LED will continue to flash once for each write that has
been made to /var/mail/root, until it also has been read.
.PP
The list of files can include files that don't yet exist.
.PP
To terminate the daemon, run:
.PP
.RS
# kill `cat /var/run/flasher.pid`
.RE
.PP
.SH X11
.I flasher
was designed to use the console to indicate file activity.  When running
.I flasher
in an X11 environment, it may be helpful to use the
.I -k
option to specify what virtual terminal X11 is running under. For example, use
.PP
.RS
# flasher -k /dev/ttyv3 ...
.RE
.PP
when running X11 on FreeBSD on virtual terminal 4.
.PP
Similarly, when using X11 on virtual terminal 8 on Linux, start the daemon
using:
.PP
.RS
# flasher -k /dev/tty8 ...
.RE
.SH OPTIONS
.TP
.B \-c
Indicate writes to the specified file using the Caps Lock LED.
.TP
.B \-k /dev/ttyXX
Use the specified tty (/dev/ttyXX) instead of the console.
.TP
.B \-n
Indicate writes to the specified file using the Num Lock LED.
.TP
.B \-s
Indicate writes to the specified file using the Scroll Lock LED.
.TP
.B \-u number
Scans the specified files for changes every `number' seconds (default: 60).
.SH EXAMPLES
The following example will flash the Scroll Lock LED to indicate
/var/log/messages writes, and the Num Lock LED for writes to
/var/mail/root:
.PP
.RS
# flasher -s /var/log/messages -n /var/mail/root
.RE
.PP
The following example will flash the Caps Lock LED to indicate writes
to either /var/log/httpd-error.log or /var/mail/root, and flash the Num
Lock LED to indicate writes to /var/log/messages.
.PP
.RS
# flasher -n /var/log/messages -c /var/log/httpd-error.log:/var/mail/root
.RE
.PP
.SH FILES
/var/run/flasher.pid \- flasher lock file
.SH DIAGNOSTICS
.I flasher
must be run as the super-user.
.PP
Relative pathnames will be converted to absolute pathnames.
.PP
After the program has daemonized, any messages will be sent to syslog.
.SH AUTHOR
Murray Nesbitt (websrc@nesbitt.ca)