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You can pass various arguments to a Perl subroutine like you do in any other programming language and they can be accessed inside the function using the special array @_. Thus the first argument to the function is in $_[0], the second is in $_[1], and so on.You can pass arrays and hashes as arguments like any scalar but passing more than one array or hash normally causes them to lose their separate identities. So we will use references ( explained in the next chapter ) to pass an array or hash.Let's try the following example, which takes a list ... Read More
The general form of a subroutine definition in Perl programming language is as follows −sub subroutine_name { body of the subroutine }The typical way of calling that Perl subroutine is as follows −subroutine_name( list of arguments );In versions of Perl before 5.0, the syntax for calling subroutines was slightly different as shown below. This still works in the newest versions of Perl, but it is not recommended since it bypasses the subroutine prototypes.&subroutine_name( list of arguments );Let's have a look into the following example, which defines a simple function and then call it. Because Perl compiles your program before ... Read More
You can use the POSIX function strftime() in Perl to format the date and time with the help of the following table. Please note that the specifiers marked with an asterisk (*) are locale-dependent.SpecifierReplaced byExample%aAbbreviated weekday name *Thu%AFull weekday name *Thursday%bAbbreviated month name *Aug%BFull month name *August%cDate and time representation *Thu Aug 23 14:55:02 2001%CA year divided by 100 and truncated to integer (00-99)20%dDay of the month, zero-padded (01-31)23%DShort MM/DD/YY date, equivalent to %m/%d/%y08/23/01%eDay of the month, space-padded ( 1-31)23%FShort YYYY-MM-DD date, equivalent to %Y-%m-%d2001-08-23%gWeek-based year, last two digits (00-99)01%GWeek-based year2001%hAbbreviated month name * (same as %b)Aug%HAn hour in 24h ... Read More
You can use the time() function in Perl to get epoch time, i.e., the numbers of seconds that have elapsed since a given date, in Unix is January 1, 1970.Example Live Demo#!/usr/local/bin/perl $epoc = time(); print "Number of seconds since Jan 1, 1970 - $epoc";OutputWhen the above code is executed, it produces the following result −Number of seconds since Jan 1, 1970 - 1361022130You can convert a given number of seconds into date and time string as follows −Example Live Demo#!/usr/local/bin/perl $datestring = localtime(); print "Current date and time $datestring"; $epoc = time(); $epoc = $epoc - 24 * 60 * 60; ... Read More
You can use localtime() function in Perl to get a list of 9-elements and later you can use the printf() function to format date and time based on your requirements as follows −Example Live Demo#!/usr/local/bin/perl ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime(); printf("Time Format - HH:MM:SS"); printf("%02d:%02d:%02d", $hour, $min, $sec);OutputWhen the above code is executed, it produces the following result −Time Format - HH:MM:SS 06:58:52
The function gmtime() in Perl works just like localtime() function but the returned values are localized for the standard Greenwich time zone. When called in list context, $isdst, the last value returned by gmtime, is always 0. There is no Daylight Saving Time in GMT.You should make a note on the fact that localtime() will return the current local time on the machine that runs the script and gmtime() will return the universal Greenwich Mean Time, or GMT (or UTC).Try the following example to print the current date and time but on GMT scale −Example Live Demo#!/usr/local/bin/perl $datestring = gmtime(); print ... Read More
Let's start with localtime() function in Perl, which returns values for the current date and time if given no arguments. Following is the 9-element list returned by the localtime function while using in list context −sec, # seconds of minutes from 0 to 61 min, # minutes of hour from 0 to 59 hour, # hours of day from 0 to 24 mday, # day of month from 1 to 31 mon, # month of year from 0 to 11 year, # year since 1900 wday, # days since sunday yday, # days since January 1st isdst # hours of ... Read More
The following table lists all operators from highest precedence to lowest in Perl Programming.
There are following miscellaneous operators supported by Perl language. Assume variable a holds 10 and variable b holds 20 then −Sr.No.Operator & Description1.Binary operator dot (.) concatenates two strings.Example− If $a = "abc", $b = "def" then $a.$b will give "abcdef"2xThe repetition operator x returns a string consisting of the left operand repeated the number of times specified by the right operand.Example− ('-' x 3) will give ---.3..The range operator .. returns a list of values counting (up by ones) from the left value to the right valueExample− (2..5) will give (2, 3, 4, 5)4++Auto Increment operator increases integer value ... Read More
There are following logical operators supported by Perl language. Assume variable $a holds true and variable $b holds false then −Sr.No.Operator & Description1andCalled Logical AND operator. If both the operands are true then the condition becomes true.Example− ($a and $b) is false. 2&&C-style Logical AND Operator copies a bit to the result if it exists in both operandsExample− ($a && $b) is false.3orCalled Logical OR Operator. If any of the two operands are non zero then condition becomes true.Example− ($a or $b) is true.4||C-style Logical OR Operator copies a bit if it exists in either operand.p>Example− ($a || $b) is true.5notCalled ... Read More