A quick and simple way to convert upper/lower case on the command line in Linux is to use the “tr” (translate) utility.
To convert uppercase to lowercase:
tr [A-Z] [a-z]
To convert lowercase to uppercase:
tr [a-z] [A-Z]
And in a shell script:
VALUE="A Mixed Case String" UPPER=`echo $VALUE | tr [a-z] [A-Z]` LOWER=`echo $VALUE | tr [A-Z] [a-z]`
I am actively submitting to the Eagle3D project, the components available on this site will be in the stock Eagle3D soon.
# A Makefile to compile NXC code using NBC # Copyright (C) 2008 Gary French # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # INCLUDEDIR =../include NBC=/usr/local/bin/nbc NBC_FLAGS=-I=$(INCLUDEDIR) #optional compiler optimizations # NBC_FLAGS=-I=$(INCLUDEDIR) -Z1 # NBC_FLAGS=-I=$(INCLUDEDIR) -Z2 #this can also be explicitly set # NXC_FILES := TheProgram.nxc NXC_FILES := $(shell ls -1 -t -F *.nxc 2>/dev/null | grep '\.nxc') RXE_FILES := $(NXC_FILES:.nxc=.rxe) BYTECODE_FILES := $(NXC_FILES:.nxc=.bytecode) LISTING_FILES := $(NXC_FILES:.nxc=.listing) SYMTABLE_FILES := $(NXC_FILES:.nxc=.symtable) #the targets can be called individually, or called from the "all" target #all: compile bytecode listing symtable all: compile compile: $(RXE_FILES) %.rxe: $(NXC_FILES) @echo "compiling $<" $(NBC) $(NBC_FLAGS) -O=$@ $< @echo bytecode: $(BYTECODE_FILES) %.bytecode: $(NXC_FILES) @echo "generating bytecode for $<" $(NBC) $(NBC_FLAGS) -b -nbc=$@ $< @echo listing: $(LISTING_FILES) %.listing: $(NXC_FILES) @echo "generating code listing for $<" $(NBC) $(NBC_FLAGS) -b -L=$@ $< @echo symtable: $(SYMTABLE_FILES) %.symtable: $(NXC_FILES) @echo "generating symbol table for $<" $(NBC) $(NBC_FLAGS) -b -Y=$@ $< @echo clean: @echo "cleaning up..." -rm $(RXE_FILES) -rm $(BYTECODE_FILES) -rm $(LISTING_FILES) -rm $(SYMTABLE_FILES) @echo .PHONY: clean bytecode listing symtable
you must be able to communicate with the NXT Brick for any of the following to be applicable. there are a few “how-to”s available, including this post.
I am using the compiler available at Next Byte Codes & Not eXactly C site. This is a simple package package to “install” (simply copying the executable from the tar/gzip to /usr/local/bin did it for me), and is wonderfully documented.
I am using a modified version of a script provided by Jan-Klaas Kollhof:
#!/bin/sh
set -e
_nbcpath=/PATH/TO/NBC/EXECUTABLE/DIRECTORY
_dirname=`dirname $1`
if [ "${_dirname}" == "." ]; then
_dirname=$(pwd)
fi
_basename=`basename $1 .nxc`
echo "compiling ${_basename}.rxe from ${_basename}.nxc..."
${_nbcpath}/nbc \
-O="${_dirname}/${_basename}.rxe" \
-nbc="${_dirname}/${_basename}.nbc" \
"${_dirname}/${_basename}.nxc"
echo "sending ${_basename}.rxe to brick..."
cd "${_dirname}"
nxt_push "${_basename}.rxe"
as should be apparent, /PATH/TO/NBC/EXECUTABLE/DIRECTORY will need to be altered to suit your environment.
the “-nbc” switch will save the generated “Next Byte Code” to YOUR_CODE_FILE_NAME.nbc. the resulting file is not only interesting to poke around in, but may help when optimizing for size.
currently, I am having some issues with nxt_python, documented here.
while working with nxt_python and a few applications written in NXC, I found I had a need to get files from the NXT Brick with a minimum of fuss. The following python script will “pull” a single file from the NXT Brick. Wildcard behavior is undefined, and is planned for version 0.2.
example usage:
[gary@motoko]# nxt_pull log.txt
code:
#!/usr/bin/env python # # nxt_pull: # Pull a file to a LEGO Mindstorms NXT brick, # based on Douglas P Lau's nxt_filer and nxt_push # Copyright (C) 2008 Gary French # Version: 0.1 # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program 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 General Public License for more details. import sys import nxt.locator from nxt.brick import FileFinder, FileReader, FileWriter def read_file( b, fname ): r = FileReader(b, fname) r.__enter__() try: f = open(fname, 'wb') print 'Pulling %s ...' % (fname), try: size = 0 for data in r: f.write(data) size += len(data) finally: f.close() print 'read %d bytes' % size finally: r.__exit__(None, None, None) if __name__ == '__main__': sock = nxt.locator.find_one_brick() #sock = nxt.locator.find_one_brick(host='00:16:53:XX:XX:XX') if sock: b = sock.connect() read_file( b, sys.argv[1] ) sock.close()
currently, to avoid a “bluetooth.BluetoothError: (115, ‘Operation now in progress’)” error, I have to:
it acts as if something is not cleaning up after itself properly.
I’m sure I’ll figure that one out, but I have more pressing concerns at the moment. if anyone has some insight on this issue I’d appreciate the comment.
current workaround:
sock = nxt.locator.find_one_brick()
to:
sock = nxt.locator.find_one_brick(host='00:16:53:XX:XX:XX')
as one might suspect, this workaround is applicable in any other similar situation.
it is vital that the following python packages are installed:
to test PyBlueZ, the following can be used (code by Albert Huang <albert@csail.mit.edu>)
#!/usr/bin/env python
import bluetooth
print "performing inquiry..."
nearby_devices = bluetooth.discover_devices(lookup_names = True)
print "found %d devices" % len(nearby_devices)
for name, addr in nearby_devices:
print " %s - %s" % (addr, name)
as I do not care for gnome, my default desktop is KDE,
what follows is my procedure for pairing with a NXT Brick.
[root@motoko]# /usr/bin/bluetooth-applet &
a Bluetooth icon will appear in your system tray,
right-click the Bluetooth icon and click “Preferences” from the popup.
on the NXT Brick, from the root menu,
the connection can now be tested with the following python code:
#!/usr/bin/env python import nxt.locator sock = nxt.locator.find_one_brick() if sock: brick = sock.connect() name, host, signal_strength, user_flash = brick.get_device_info() print 'NXT brick name: %s' % name print 'Host address: %s' % host print 'Bluetooth signal strength: %s' % signal_strength print 'Free user flash: %s' % user_flash sock.close()
not much yet, but with two development forks we’ll probably have something workable soon.
as of 11/16/2008:
a few test ideas.
took me a while to figure this one out, you’d think getting a standarized date/time would be a bit simpler…
put the following in a class
private final static SimpleDateFormat dateFormat;
static {
//as per ISO 8601
dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
//make sure the formatter requires an exact string
dateFormat.setLenient(false);
//set "timezone" to Universal Time Coordinates (GMT adjusted by leap seconds)
dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
}
and the following elsewhere in the class:
//to create a string String nowString = dateFormat.format(new Date()); //to parse a proper string to a date Date nowDate = dateFormat.parse(nowString);
an ActionListener is an interface for receiving action events, a class that should process action events should implement this interface, then be registered with a component.
an ActionListener can be registered with any object capable of it, typically this is an instance of an AbstactButton class like a JButton or JMenuItem.
Continue reading ‘Java ActionEvents and ActionListeners’ »
pdf is a document format. there are occasions where I find it easier to work with one large document rather than several single documents (most recently, while working with several spec sheets for electronic components), the following command will join two or more *.pdfs into a single document using ghostscript.
gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=OUTPUT.pdf INPUT01.pdf INPUT02.pdf ...
-dBATCH - exit after last file
-dNOPAUSE - no pause after page
-q - “quiet”, fewer messages
-sDEVICE=<devname> - select device, in this case the pdf writer
-sOutputFile=<file> - select output file
the following were not, but could be, included:
-g<width>x<height> - page size in pixels
-r<res> - pixels/inch resolution
an example of the cloth and wind effects available in Blender 2.45
Blender just keeps getting better…
declaring the variables:
int A; int *pA; int B; int *pB;
at this point, A is a container for an integer, and B is a container for a pointer to an integer.
in the body of the code, a “*” can be seen as “the value pointed to by”, and “&” can be seen as “the address of”, as in (using the above delarations):
A = 100; //directly sets the value of A pA = &A; //now pA contains the address of A pB = pA; //now pB contains the value of pA, which is the address of A B = *pB; //now B contains the value that is pointed to by pB
now both A and Bcontain “100″, and both pA and pB contain the location of A.
cout << "A: " << A << endl; //displays value in A cout << "B: " << B << endl; //displays value in B cout << "pA: " << pA << endl; //displays address in pA cout << "pB: " << pB << endl; //displays address in pB cout << "*pA: " << *pA << endl; //displays value pointed to by pA cout << "*pB: " << *pB << endl; //displays value pointed to by pB cout << endl;
would show something like the following (note that [ADDRESS] would actually be a memory location):
A: 100 B: 100 pA: 0x[ADDRESS] pB: 0x[ADDRESS] *pA: 100 *pB: 100
at this point, setting the value held by A could be done in any of the following ways:
A = 200; *pA = 200; *pB = 200;
*pB can be used to set the value of A because pB contains the address of A.
note that B contains the same value as is in A, but is now independant of it. in the above example, A was set, then pA was set to it’s address, then pB was set to the contents of pA, then B was set the the value pointed to by pB.
pdf is a document format. on the occasion where it is easier to reference an image rather than the full document, the following command will convert the pdf.
convert -density 96x96 -trim INPUTFILE.pdf OUTPUTFILE.jpg
-density is the image density in pixels per square inch
-trim will trim the image edges
the output will be in the form of OUTPUTFILE-#.jpg, where # is an increasing “page” number.
this command will also work for OUTPUTFILE.png, OUTPUTFILE.gif, et. al..
also, imagemagick uses ghostscript to convert, so the quality of the final images will only be as good as ghostscript can provide.
