Brad Lucas

Programming, Clojure and other interests

Ethereum Reset Local Blockchain Geth

July 15, 2017

Returning to some Ethereum work I wanted to reset my old local blockchain by deleting it an starting from scratch. Here are notes to describe what to do.

Ethereum Installation Directory

On OSX Ethereum installs in $HOME/Library/Ethereum. The public data is in geth while the testnet directory contains the testnet data.

Remove blockchain and state databases

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Programming Competitions

July 14, 2017

The other week I saw this post about programming competitions and how they supposedly correlate negatively to job performance. This was according to Peter Norvig.

I found this interesting because as most will know the typical work of a programmer is very different from a programming competition.

After looking around a bit I found a Hacker News post for the same blog page with some interesting comments.

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July 13, 2017

An old Perl script for replacing a string within multiple files.

# Replaces a string within multiple files
# specified on the command line

$mv = '/bin/mv';

$op = shift || die("Usage: $0 perlexpr [filenames]\n");
print "$op\n";
print "@ARGV\n";

if (!@ARGV) {
  @ARGV = <STDIN>;

foreach $file (@ARGV) {
  if (!-f $file) { print "Skipping non-regular file: $file\n"; next; }
  if (-B $file) { print "Skipping binary file: $file\n"; next; }

  $outfile = "/tmp/$file.$$";

  open(FILE, $file) || die("Couldn't open $file: $!\n&quot;");
  undef $/;
  $_ = <FILE>;

  if (eval $op) {
    open(OFILE, "> $outfile") || die("Couldn't open $outfile: $!\n");
    print OFILE;

    system($mv, '-f', $file, "$file.bak");
    system($mv, '-f', $outfile, $file);

    print "File changed: $file\n";
  else {
    print "No change to file: $file\n";


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July 12, 2017

Show the amount of disk space the larger directories under your home directory are taking.


pushd $HOME

du -sk * | sort -nr | head


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Travel Day

July 11, 2017

Travelling today. Looks like 13 hours door to door.

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