How to Understand Epoch & Unix Timestamp | Epoch Converter

epoch-unix-timestamp

What is epoch time?

The Unix epoch (or Unix time or POSIX time or Unix timestamp) is the number of seconds that have elapsed since January 1, 1970 (midnight UTC/GMT), not counting leap seconds (in ISO 8601: 1970-01-01T00:00:00Z). Literally speaking the epoch is Unix time 0 (midnight 1/1/1970), but ‘epoch’ is often used as a synonym for ‘Unix time’. Many Unix systems store epoch dates as a signed 32-bit integer, which might cause problems on January 19, 2038 (known as the Year 2038 problem or Y2038).

Human readable time Seconds
1 hour 3600 seconds
1 day 86400 seconds
1 week 604800 seconds
1 month (30.44 days) 2629743 seconds
1 year (365.24 days) 31556926 seconds

How to get the current epoch time in …

Perl time
PHP time()
Ruby Time.now (or Time.new). To display the epoch: Time.now.to_i
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())
R as.numeric(Sys.time())
Erlang calendar:datetime_to_gregorian_seconds(calendar:now_to_universal_time( now()))-719528*24*3600.
MySQL SELECT unix_timestamp(now()) More info (+ negative epochs)
PostgreSQL SELECT extract(epoch FROM now());
Oracle PL/SQL SELECT (SYSDATE – TO_DATE(’01/01/1970 00:00:00′, ‘MM-DD-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.
Tcl/Tk clock seconds
Unix/Linux Shell 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 the Perl Epoch routines
PHP mktime(hour, minute, second, month, day, year) More info
Ruby Time.local(year, month, day, hour, minute, second, usec ) (or Time.gm 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 (“MM/dd/yyyy HH:mm:ss”).parse(“01/01/1970 01:00:00”).getTime();
VBScript/ASP DateDiff(“s”, “01/01/1970 00:00:00”, time field) More info
C Use the C Epoch Converter routines
R as.numeric(as.POSIXct(“MM/dd/yyyy HH:mm:ss”, origin=”1970-01-01″))
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 Shell 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 the Perl Epoch routines
PHP date(output format, epoch); Output format example: ‘r’ = RFC 2822 date More info
Ruby Time.at(epoch)
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 info
Java String date = new java.text.SimpleDateFormat(“MM/dd/yyyy HH:mm:ss”).format(new java.util.Date (epoch*1000));
VBScript/ASP DateAdd(“s”, epoch, “01/01/1970 00:00:00”) More info
C Use the C Epoch Converter routines
R as.POSIXct(epoch, origin=”1970-01-01″)
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 info Older versions: SELECT TIMESTAMP WITH TIME ZONE ‘epoch’ + epoch * INTERVAL ‘1 second’;
Oracle PL/SQL SELECT to_date(’01-JAN-1970′,’dd-mon-yyyy’)+(1326357743/60/60/24) from dual
Replace 1326357743 with epoch.
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 time zones: =((A1 +/- time zone adjustment) / 86400) + 25569.
Crystal Reports DateAdd(“s”, {EpochTimeStampField}-14400, #1/1/1970 00:00:00#) -14400 used for Eastern Standard Time. See Time Zones.
JavaScript Use the JavaScript Date object
Tcl/Tk clock format 1325376000 More info
Unix/Linux Shell 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.

Reference

http://www.epochconverter.com/

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Understand Ant command line arguments with Examples

ant-command-line-arguments

Several tasks take arguments that will be passed to another process on the command line. To make it easier to specify arguments that contain space characters, nested arg elements can be used.

value – a single command-line argument; can contain space characters.

file – The name of a file as a single command-line argument; will be replaced with the absolute filename of the file.

path – A string that will be treated as a path-like string as a single command-line argument; you can use ; or : as path separators and Ant will convert it to the platform’s local conventions.

pathref – Reference to a path defined elsewhere. Ant will convert it to the platform’s local conventions.

line – a space-delimited list of command-line arguments.

It is highly recommended to avoid the line version when possible. Ant will try to split the command line in a way similar to what a (Unix) shell would do, but may create something that is very different from what you expect under some circumstances.

Examples

<arg value=”-l -a”/>

is a single command-line argument containing a space character.

<arg line=”-l -a”/>

represents two separate command-line arguments.

<arg path=”/dir;/dir2:\dir3″/>

is a single command-line argument with the value \dir;\dir2;\dir3 on DOS-based systems and /dir:/dir2:/dir3 on Unix-like systems.

Command-line Options Summary
ant [options] [target [target2 [target3] …]]

Options:
-help, -h Displays help information describing the Ant command and its options
-projecthelp, -p Print project help information
-version Print the version information and exit
-diagnostics Print information that might be helpful to diagnose or report problems.
-quiet, -q Suppresses most messages not originated by an echo task in the buildfile
-verbose, -v Displays detailed messages for every operation during a build.
-debug, -d Print debugging information
-emacs, -e Produce logging information without adornments
-lib <path> Specifies a path to search for jars and classes
-logfile <file> Use given file for log
-l <file> Use given file for log
-logger <classname> Specifies a class to handle Ant logging.
-listener <classname> Add an instance of class as a project listener
-noinput Do not allow interactive input
-buildfile <file> Use given buildfile
-file <file> Use given buildfile
-f <file> Use given buildfile
-D<property>=<value> Defines a property name-value pair on the command line.
-keep-going, -k execute all targets that do not depend on failed target(s)
-propertyfile <name> load all properties from file with -D properties taking precedence
-inputhandler <class> the class which will handle input requests
-find <file> Search for buildfile towards the root of the filesystem and use it
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