Category Archives: misc

#include <stdio .h>
#include <iostream>
using namespace std;
int main()
  int sum = 0;
  for(int x = 0; x < 1000; ++x) {
  std::cout << ". ";
  if (x % 3 ==0 || x % 5 == 0) {
    std::cout << x << " ";
    sum += x;
  std::cout << "\nSum of numbers which can be divided by 3 and 5 is " << sum << "\n";
  return 0;

date crap

How to get the current epoch time in …

Perl time
PHP time()
Ruby (or To display the epoch:
Python import time first, then time.time()
Java long epoch = System.currentTimeMillis()/1000;
Microsoft .NET C# epoch = (DateTime.Now.ToUniversalTime().Ticks - 621355968000000000) / 10000000;
VBScript/ASP DateDiff("s", "01/01/1970 00:00:00", Now())
Erlang calendar:datetime_to_gregorian_seconds(calendar:now_to_universal_time( now()))-719528*24*3600.
MySQL SELECT unix_timestamp(now()) More information
PostgreSQL SELECT extract(epoch FROM now());
Oracle PL/SQL SELECT (SYSDATE - TO_DATE('01-01-1970 00:00:00', 'DD-MM-YYYY HH24:MI:SS')) *
24 * 60 * 60 FROM DUAL
SQL Server SELECT DATEDIFF(s, '1970-01-01 00:00:00', GETUTCDATE())
JavaScript Math.round(new Date().getTime()/1000.0) getTime() returns time in milliseconds.
Unix/Linux date +%s
PowerShell Get-Date -UFormat "%s" Produces: 1279152364.63599
Other OS’s Command line: perl -e "print time" (If Perl is installed on your system)

Convert from human readable date to epoch

Perl Use these Perl Epoch routines
PHP mktime(hour, minute, second, month, day, year) More information
Ruby Time.local(year, month, day, hour, minute, second, usec ) (or for GMT/UTC input). To display add .to_i
Python import time first, then int(time.mktime(time.strptime('2000-01-01 12:34:00', '%Y-%m-%d %H:%M:%S'))) - time.timezone
Java long epoch = new java.text.SimpleDateFormat ("dd/MM/yyyy HH:mm:ss").parse("01/01/1970 01:00:00");
VBScript/ASP DateDiff("s", "01/01/1970 00:00:00", time field) More information
MySQL SELECT unix_timestamp(time) Time format: YYYY-MM-DD HH:MM:SS or YYMMDD or YYYYMMDD
More on using Epoch timestamps with MySQL
PostgreSQL SELECT extract(epoch FROM date('2000-01-01 12:34'));
With timestamp: SELECT EXTRACT(EPOCH FROM TIMESTAMP WITH TIME ZONE '2001-02-16 20:38:40-08');
With interval: SELECT EXTRACT(EPOCH FROM INTERVAL '5 days 3 hours');
SQL Server SELECT DATEDIFF(s, '1970-01-01 00:00:00', time field)
JavaScript use the JavaScript Date object
Unix/Linux date +%s -d"Jan 1, 1980 00:00:01" Replace ‘-d’ with ‘-ud’ to input in GMT/UTC time.

Convert from epoch to human readable date

Perl Use these Perl Epoch routines
PHP date(output format, epoch); Output format example: ‘r’ = RFC 2822 date More information
Python import time first, then time.strftime("%a, %d %b %Y %H:%M:%S +0000", time.localtime(epoch)) Replace time.localtime with time.gmtime for GMT time. More information
Java String date = new java.text.SimpleDateFormat("dd/MM/yyyy HH:mm:ss").format(new java.util.Date (epoch*1000));
VBScript/ASP DateAdd("s", epoch, "01/01/1970 00:00:00") More information
MySQL from_unixtime(epoch, optional output format) The default output format is YYY-MM-DD HH:MM:SS more …
PostgreSQL PostgreSQL version 8.1 and higher: SELECT to_timestamp(epoch); More information Older versions: SELECT TIMESTAMP WITH TIME ZONE 'epoch' + epoch * INTERVAL '1 second';
SQL Server DATEADD(s, epoch, '1970-01-01 00:00:00')
Microsoft Excel =(A1 / 86400) + 25569 Format the result cell for date/time, the result will be in GMT time (A1 is the cell with the epoch number). For other timezones: =((A1 +/- timezone adjustment) / 86400) + 25569.
Crystal Reports DateAdd("s", {EpochTimeStampField}-14400, #1/1/1970 00:00:00#) -14400 used for Eastern Standard Time. See Timezones.
JavaScript use the JavaScript Date object
Unix/Linux date -d @1190000000 Replace 1190000000 with your epoch, needs recent version of ‘date’. Replace ‘-d’ with ‘-ud’ for GMT/UTC time.
PowerShell Function get-epochDate ($epochDate) { [timezone]::CurrentTimeZone.ToLocalTime(([datetime]'1/1/1970').AddSeconds($epochDate)) }, then use: get-epochDate 1279152364. Works for Windows PowerShell v1 and v2
Other OS’s Command line: perl -e "print scalar(localtime(epoch))" (If Perl is installed) Replace ‘localtime’ with ‘gmtime’ for GMT/UTC time.

Window stacking in VIM

Stolen shamelessly from this site.

map <c -J> </c><c -W>j</c><c -W>_
map </c><c -K> </c><c -W>k</c><c -W>_
set wmh=0

The first two lines allow you to switch between splits much more smoothly — just press to open and maximize the split below the current one and to open and maximize the split above the current one. I chose these mappings because they correspond to vi’s default up and down keys, you might want to use different key combinations if you’ve ever used an editor that had hotkeys for moving from one open file to another.

The last line allows splits to reduce their size to a single line (which includes the filename and position); this saves a lot of space when you have many splits open. By default, vim forces splits to include an additional line that contains the line of text the cursor was on in that file.

This gives you some sort of stacking functionality like in wmii

Too Many Links

There are too many hard links to a file or directory on a filesystem. The exact number allowed is file-system dependent. Eg /usr/src/linux-2.4.19/include/linux/sysv_fs.h contains

enum {
XENIX_LINK_MAX = 126, /* ?? / SYSV_LINK_MAX = 126, / 127? 251? / V7_LINK_MAX = 126, / ?? */ COH_LINK_MAX = 10000,

while /usr/src/linux-2.4.19/include/linux/ext3_fs.h has

define EXT3_LINK_MAX 32000

and /usr/src/linux-2.4.19/include/linux/reiserfs_fs.h has


(for maximum unsigned integer on the system).

This could be caused by a directory having too many subdirectories (each subdirectory has .. as a hardlink to it’s parent directory which causes that directory’s hardlink count to be increased by one. So yes, this does mean that you are limited to 32000 subdirectories in one directory in ext3, even if you have hashdirs enabled.) As a consequence of this you can stat(2) a directory and add one (for ..) and you will know how many directories are in the current directory. (or subtract one (for .) to find out how many subdirectories there are).

Some file systems (such as FAT) don’t have hardlinks so the hardlink count can’t overflow, and you can’t rely on the hardlink count of a directory to be representive of how many subdirectories it has.

What a confusing world we live in.