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244 lines
5.1 KiB
244 lines
5.1 KiB
.TH "GPIO" "14 June 2012" "Command-Line access to Raspberry Pi and PiFace GPIO"
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.SH NAME
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gpio \- Command-line access to Raspberry Pi and PiFace GPIO
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.SH SYNOPSIS
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.B gpio
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.B \-v
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.PP
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.B gpio
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.B [ \-g ]
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.B read/write/pwm/mode ...
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.PP
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.B gpio
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.B [ \-p ]
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.B read/write/mode
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.B ...
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.PP
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.B gpio
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.B unexportall/exports
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.PP
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.B gpio
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.B export/edge/unexport
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.B ...
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.PP
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.B gpio
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.B drive
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group value
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.PP
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.B gpio
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.B pwm-bal/pwm-ms
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.PP
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.B gpio
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.B pwmr
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range
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.PP
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.B gpio
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.B load \ i2c/spi
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.PP
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.B gpio
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.B gbr
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channel
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.PP
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.B gpio
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.B gbw
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channel value
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.SH DESCRIPTION
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.B GPIO
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is a swiss army knofe of a command line tool to allow the user easy
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access to the GPIO pins on the Raspberry Pi and the SPI A/D and D/A
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convertors on the Gertboard. It's designed for simple testing and
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diagnostic purposes, but can be used in shell scripts for general if
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somewhat slow control of the GPIO pins.
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Additionally, it can be used to set the exports in the \fI/sys/class/gpio\fR
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system directory to allow subsequent programs to use the \fR/sys/class/gpio\fR
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interface without needing to be run as root.
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.SH OPTIONS
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.TP
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.B \-v
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Output the current version
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.TP
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.B \-g
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Use the BCM_GPIO pins numbers rather than wiringPi pin numbers.
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.TP
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.B \-p
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Use the PiFace interface board and its corresponding pin numbers.
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.TP
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.B read
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Read the digital value of the given pin and print 0 or 1 to represent the
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respective logic levels.
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.TP
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.B write
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Write the given value (0 or 1) to the pin.
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.TP
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.B pwm
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Write a PWM value (0-1023) to the given pin.
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.TP
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.B mode
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Set a pin into \fIinput\fR, \fIoutput\fR or \fIpwm\fR mode. Can also
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use the literals \fIup\fR, \fIdown\fR or \fItri\fR to set the internal
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pull-up, pull-down or tristate (off) controls.
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.TP
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.B unexportall
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Un-Export all the GPIO pins in the /sys/class/gpio directory.
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.TP
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.B exports
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Print a list (if any) of all the exported GPIO pins and their current values.
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.TP
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.B export
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Export a GPIO pin in the \fI/sys/class/gpio\fR directory. Use like the
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mode command above however only \fIin\fR and \fIout\fR are supported at
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this time. Note that the pin number is the \fBBCM_GPIO\fR number and
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not the wiringPi number.
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Once a GPIO pin has been exported, the \fBgpio\fR program changes the
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ownership of the \fI/sys/class/gpio/gpioX/value\fR and if present in
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later kernels, the \fI/sys/class/gpio/gpioX/edge\fR pseudo files to
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that of the user running the \fBgpio\fR program. This means that you
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can have a small script of gpio exports to setup the gpio pins as your
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program requires without the need to run anything as root, or with the
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sudo command.
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.TP
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.B edge
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This exports a GPIO pin in the \fI/sys/class/gpio\fR directory, set
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the direction to input and set the edge interrupt method to \fInone\fR,
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\fIrising\fR, \fIfalling\fR or \fIboth\fR. Use like the export command
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above and note that \fBBCM_GPIO\fR pin number is used not not wiringPi pin
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numbering.
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Like the export commands abovem ownership is set to that of the
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calling user, allowing subsequent access from user programs without
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requiring root/sudo.
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.TP
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.B unexport
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Un-Export a GPIO pin in the /sys/class/gpio directory.
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.TP
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.B drive
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group value
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Change the pad driver value for the given pad group to the supplied drive
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value. Group is 0, 1 or 2 and value is 0-7. Do not use unless you are
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absolutely sure you know what you're doing.
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.TP
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.B pwm-bal/pwm-ms
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Change the PWM mode to balanced (the default) or mark:space ratio (traditional)
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.TP
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.B pwmr
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Change the PWM range register. The default is 1024.
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.TP
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.B load i2c/spi
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This loads the i2c or the spi drivers into the system and changes the permissions on
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the associated /dev/ entries so that the current user has access to them.
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.TP
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.B gbr
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channel
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This reads the analog to digital convertor on the Gertboard on the given
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channel. The board jumpers need to be in-place to do this operation.
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.TP
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.B gbw
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channel value
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This writes the supplied value to the output channel on the Gertboards
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SPI digital to analogue convertor.
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The board jumpers need to be in-place to do this operation.
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.SH "WiringPi vs. GPIO Pin numbering"
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.PP
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.TS
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r r l.
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WiringPi GPIO Function
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_
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0 17
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1 18 (PWM)
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2 21
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3 22
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4 23
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5 24
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6 25
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7 4
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8 0 SDA0
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9 1 SCL0
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10 8 SPI CE0
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11 7 SPI CE1
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12 10 SPI MOSI
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13 9 SPI MISO
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14 11 SPI SCLK
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15 14 TxD
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16 15 RxD
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.TE
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.SH FILES
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.TP 2.2i
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.I gpio
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executable
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.SH EXAMPLES
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.TP 2.2i
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gpio mode 4 output # Set pin 4 to output
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.PP
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gpio -g mode 23 output # Set GPIO pin 23 to output (same as WiringPi pin 4)
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.PP
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gpio mode 1 pwm # Set pin 1 to PWM mode
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.PP
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gpio pwm 1 512 # Set pin 1 to PWM value 512 - half brightness
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.PP
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gpio export 17 out # Set GPIO Pin 17 to output
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.PP
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gpio export 0 in # Set GPIO Pin 0 (SDA0) to input.
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.PP
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gpio -g read 0 # Read GPIO Pin 0 (SDA0)
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.SH "NOTES"
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When using the \fIexport\fR, \fIedge\fR or \fIunexport\fR commands, the
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pin numbers are \fBalways\fR native BCM_GPIO numbers and never wiringPi
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pin numbers.
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.SH "SEE ALSO"
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.LP
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WiringPi's home page
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.IP
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https://projects.drogon.net/raspberry-pi/wiringpi/
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.SH AUTHOR
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Gordon Henderson
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.SH "REPORTING BUGS"
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Report bugs to <projects@drogon.net>
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.SH COPYRIGHT
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Copyright (c) 2012 Gordon Henderson
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This is free software; see the source for copying conditions. There is NO
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warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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