Difference between revisions of "PERL/C2/Comments-in-Perl/English-timed"
From Script | Spoken-Tutorial
PoojaMoolya (Talk | contribs) |
|||
(3 intermediate revisions by one other user not shown) | |||
Line 4: | Line 4: | ||
|- | |- | ||
|00:00 | |00:00 | ||
− | | Welcome to the spoken tutorial on | + | | Welcome to the spoken tutorial on '''Comments in Perl'''. |
|- | |- | ||
Line 12: | Line 12: | ||
|- | |- | ||
|00:08 | |00:08 | ||
− | | | + | |comments in '''Perl'''. |
|- | |- | ||
|00:10 | |00:10 | ||
− | |I am using '''Ubuntu | + | |I am using '''Ubuntu Linux 12.04''' operating system and '''Perl''' '''5.14.2 ''' |
|- | |- | ||
|00:18 | |00:18 | ||
− | |that is, '''Perl''' revision 5 version 14 and subversion 2 | + | |that is, '''Perl''' revision 5 version 14 and subversion 2. |
|- | |- | ||
Line 32: | Line 32: | ||
|- | |- | ||
|00:31 | |00:31 | ||
− | |You should have | + | |You should have basic knowledge of compiling, executing and variables in Perl. |
|- | |- | ||
|00:37 | |00:37 | ||
− | |If not, please go through the relevant spoken tutorials on the spoken tutorial website | + | |If not, please go through the relevant spoken tutorials on the spoken tutorial website. |
|- | |- | ||
Line 44: | Line 44: | ||
|- | |- | ||
| 00:47 | | 00:47 | ||
− | |'''Single Line''' | + | |'''Single Line''' , ''' Multi-Line'''. |
− | + | ||
− | + | ||
− | + | ||
− | + | ||
|- | |- | ||
|00:49 | |00:49 | ||
Line 55: | Line 51: | ||
|- | |- | ||
|00:55 | |00:55 | ||
− | | to add one liner text to explain the functionality of a piece of code | + | | to add one liner text to explain the functionality of a piece of code. |
|- | |- | ||
|01:01 | |01:01 | ||
− | |This type of comment starts with the symbol ''' # (hash) '''. | + | |This type of comment starts with the symbol '''# (hash)'''. |
|- | |- | ||
Line 71: | Line 67: | ||
|- | |- | ||
| 01:19 | | 01:19 | ||
− | |Once again | + | |Once again reminding you that the ampersand is used to free the '''command prompt''' in the '''terminal''', now press '''Enter'''. |
|- | |- | ||
Line 79: | Line 75: | ||
|- | |- | ||
|01:29 | |01:29 | ||
− | |'''hash Declaring count variable | + | |'''hash Declaring count variable''' press '''Enter'''. |
|- | |- | ||
|01:37 | |01:37 | ||
− | |'''dollar count space equal to space 1 semicolon''' | + | |'''dollar count space equal to space 1 semicolon''' press '''Enter'''. |
|- | |- | ||
|01:45 | |01:45 | ||
− | |'''print space double quotes Count is dollar count slash n''' | + | |'''print space double quotes Count is dollar count slash n''' double quotes complete '''semicolon space hash Prints Count is 1''' |
|- | |- | ||
|02:03 | |02:03 | ||
− | | Now | + | | Now save this file by pressing '''Ctrl S''' and execute the '''Perl''' script. |
|- | |- | ||
| 02:08 | | 02:08 | ||
− | | Switch to the '''Terminal''' | + | | Switch to the '''Terminal''' and type '''perl hyphen c comments dot pl''' and press '''Enter.''' |
|- | |- | ||
|02:18 | |02:18 | ||
− | |This tells us that there is no syntax error | + | |This tells us that there is no syntax error. |
|- | |- | ||
| 02:21 | | 02:21 | ||
− | |Now type '''perl comments dot pl''' and press '''Enter.''' | + | |Now type: '''perl comments dot pl''' and press '''Enter.''' |
|- | |- | ||
Line 115: | Line 111: | ||
|- | |- | ||
| 02:36 | | 02:36 | ||
− | |In '''gedit''', go to the first line and press | + | |In '''gedit''', go to the first line and press '''Enter'''. |
|- | |- | ||
Line 127: | Line 123: | ||
|- | |- | ||
| 02:52 | | 02:52 | ||
− | |This line in '''Perl''' is called as | + | |This line in '''Perl''' is called as '''shebang line''' and is the first line in a '''Perl '''program. |
|- | |- | ||
Line 135: | Line 131: | ||
|- | |- | ||
|03:03 | |03:03 | ||
− | | | + | |Note: Though this line starts with hash symbol, it will not be considered as a single line comment by '''Perl'''. |
|- | |- | ||
|03:11 | |03:11 | ||
− | |Now let us look at multiline comments | + | |Now let us look at multiline comments. |
|- | |- | ||
| 03:13 | | 03:13 | ||
− | |'''Multi Line''' This type of comment is used | + | |'''Multi Line:''' This type of comment is used |
|- | |- | ||
|03:17 | |03:17 | ||
− | |when user wants to comment a piece of code or to add description/usage of piece of code | + | |when user wants to comment a piece of code or to add description/usage of piece of code. |
|- | |- | ||
|03:25 | |03:25 | ||
− | |This type of comment starts with the symbol '''equal to head''' and ends with '''equal to cut''' | + | |This type of comment starts with the symbol '''equal to head''' and ends with '''equal to cut'''. |
|- | |- | ||
| 03:33 | | 03:33 | ||
− | | | + | |Let's switch back to '''gedit''' and type the following in the '''comments dot pl '''file. |
|- | |- | ||
|03:39 | |03:39 | ||
− | | | + | |At the end of file, type: '''equal to head''', press '''Enter'''. |
|- | |- | ||
|03:45 | |03:45 | ||
− | |'''print space double quote count variable is | + | |'''print space double quote count variable is used for counting purpose''' double quote complete press '''Enter'''. |
|- | |- | ||
Line 175: | Line 171: | ||
|- | |- | ||
| 04:05 | | 04:05 | ||
− | | On the '''Terminal''', type '''perl hyphen c comments dot pl''' and press '''Enter'''. | + | | On the '''Terminal''', type: '''perl hyphen c comments dot pl''' and press '''Enter'''. |
|- | |- | ||
|04:13 | |04:13 | ||
− | |No syntax error | + | |No syntax error. |
|- | |- | ||
| 04:15 | | 04:15 | ||
− | | | + | | So let us execute it, '''perl comments dot pl''' |
|- | |- | ||
| 04:21 | | 04:21 | ||
− | | It will show the same output as before. '''Count is 1''' | + | | It will show the same output as before. '''Count is 1'''. |
|- | |- | ||
|04:27 | |04:27 | ||
− | | It does not print the sentence | + | | It does not print the sentence “count variable is used for counting purpose”. |
|- | |- | ||
|04:32 | |04:32 | ||
− | | This is because we commented the portion using '''equal to head''' and '''equal to cut''' | + | | This is because we commented the portion using '''equal to head''' and '''equal to cut'''. |
|- | |- | ||
Line 207: | Line 203: | ||
|- | |- | ||
| 04:52 | | 04:52 | ||
− | | | + | | Please note, there should not be any leading or trailing space(s) before ''''=' ''' (equal to sign) and after the '''head''', '''cut''', '''begin''' or '''end''' word. |
|- | |- | ||
|05:02 | |05:02 | ||
− | | | + | | Open the '''Terminal''' once again. |
|- | |- | ||
| 05:05 | | 05:05 | ||
− | |And Type - ''' | + | |And Type - ''' gedit commentsExample dot pl space &''' and press '''Enter'''. |
|- | |- | ||
− | | | + | |05:15 |
− | | | + | |Type the following commands as shown on the screen. |
|- | |- | ||
|05:19 | |05:19 | ||
− | |Here I am declaring two variables '''firstNum '''and '''secondNum '''and I am assigning some values to them. | + | |Here, I am declaring two variables '''firstNum '''and '''secondNum '''and I am assigning some values to them. |
|- | |- | ||
Line 231: | Line 227: | ||
|- | |- | ||
|05:32 | |05:32 | ||
− | |Now I added these two numbers and assign the value to a third variable named addition. | + | |Now I added these two numbers and assign the value to a third variable named '''addition'''. |
|- | |- | ||
|05:39 | |05:39 | ||
− | |Next I want to print the value using print command. | + | |Next, I want to print the value using '''print''' command. |
|- | |- | ||
Line 243: | Line 239: | ||
|- | |- | ||
|05:49 | |05:49 | ||
− | |On terminal type '''perl hyphen c commentsExample dot pl''', press '''Enter.''' | + | |On terminal, type: '''perl hyphen c commentsExample dot pl''', press '''Enter.''' |
|- | |- | ||
|05:57 | |05:57 | ||
− | |There is no syntax error | + | |There is no syntax error. |
|- | |- | ||
|05:59 | |05:59 | ||
− | |So execute the script by typing | + | |So, execute the script by typing |
|- | |- | ||
|06:01 | |06:01 | ||
− | |'''perl commentsExample dot pl''' press | + | |'''perl commentsExample dot pl''' press '''Enter.''' |
|- | |- | ||
|06:07 | |06:07 | ||
− | | It will show the following output. '''Addition is 30''' | + | | It will show the following output. '''Addition is 30'''. |
|- | |- | ||
Line 267: | Line 263: | ||
|- | |- | ||
|06:16 | |06:16 | ||
− | |Here we learnt | + | |Here, we learnt to add comments in '''Perl'''. |
|- | |- | ||
|06:19 | |06:19 | ||
|Write a perl script to find square of a number. | |Write a perl script to find square of a number. | ||
+ | |||
|- | |- | ||
|06:23 | |06:23 | ||
− | |Explain the functionality of the code written using | + | |Explain the functionality of the code written using '''single line comment''' & '''multiline Comment'''. |
|- | |- | ||
| 06:30 | | 06:30 | ||
− | | Watch the video available at the following link | + | | Watch the video available at the following link. |
|- | |- | ||
|06:34 | |06:34 | ||
− | |It | + | |It summarizes the Spoken Tutorial project. |
|- | |- | ||
|06:37 | |06:37 | ||
− | |If you do not have good bandwidth, you can download and watch it | + | |If you do not have good bandwidth, you can download and watch it. |
|- | |- | ||
− | | | + | |06:42 |
− | | | + | |The Spoken Tutorial Project Team: |
|- | |- | ||
|06:44 | |06:44 | ||
− | |Conducts workshops using spoken tutorials | + | |Conducts workshops using spoken tutorials. |
|- | |- | ||
|06:48 | |06:48 | ||
− | |Gives certificates to those who pass an online test | + | |Gives certificates to those who pass an online test. |
|- | |- | ||
|06:51 | |06:51 | ||
− | |For more details, please write to contact at spoken hyphen tutorial dot org | + | |For more details, please write to contact at spoken hyphen tutorial dot org. |
|- | |- | ||
− | | 06:58 | + | |06:58 |
− | | Spoken Tutorial Project is a part of the Talk to a Teacher project | + | | Spoken Tutorial Project is a part of the Talk to a Teacher project. |
|- | |- | ||
|07:03 | |07:03 | ||
− | |It is supported by the National Mission on Education through ICT, MHRD, Government of India | + | |It is supported by the National Mission on Education through ICT, MHRD, Government of India. |
|- | |- | ||
|07:11 | |07:11 | ||
− | |More information on this | + | |More information on this mission is available at the following link. |
|- | |- | ||
| 07:15 | | 07:15 | ||
− | | | + | |Hope you enjoyed this '''Perl''' tutorial. This is Amol Brahmankar, signing off. |
Thanks for joining. | Thanks for joining. | ||
|} | |} |
Latest revision as of 15:03, 10 March 2017
Time | Narration |
---|---|
00:00 | Welcome to the spoken tutorial on Comments in Perl. |
00:05 | In this tutorial, we will learn about |
00:08 | comments in Perl. |
00:10 | I am using Ubuntu Linux 12.04 operating system and Perl 5.14.2 |
00:18 | that is, Perl revision 5 version 14 and subversion 2. |
00:23 | I will also be using the gedit Text Editor. |
00:27 | You can use any text editor of your choice. |
00:31 | You should have basic knowledge of compiling, executing and variables in Perl. |
00:37 | If not, please go through the relevant spoken tutorials on the spoken tutorial website. |
00:43 | Commenting a piece of code in Perl can be done in two ways: |
00:47 | Single Line , Multi-Line. |
00:49 | This type of comment is used when user wants to comment a single line of code or |
00:55 | to add one liner text to explain the functionality of a piece of code. |
01:01 | This type of comment starts with the symbol # (hash). |
01:05 | Here is a demo. Let us open a new file in the Text Editor. |
01:11 | Open the Terminal and type - gedit comments dot pl space & |
01:19 | Once again reminding you that the ampersand is used to free the command prompt in the terminal, now press Enter. |
01:27 | Now type the following commands. |
01:29 | hash Declaring count variable press Enter. |
01:37 | dollar count space equal to space 1 semicolon press Enter. |
01:45 | print space double quotes Count is dollar count slash n double quotes complete semicolon space hash Prints Count is 1 |
02:03 | Now save this file by pressing Ctrl S and execute the Perl script. |
02:08 | Switch to the Terminal and type perl hyphen c comments dot pl and press Enter. |
02:18 | This tells us that there is no syntax error. |
02:21 | Now type: perl comments dot pl and press Enter. |
02:28 | It will show the following output - Count is 1 |
02:33 | Let us switch back to gedit. |
02:36 | In gedit, go to the first line and press Enter. |
02:40 | Go back to the first line and type the following command. |
02:44 | Hash exclamation mark slash usr slash bin slash perl |
02:52 | This line in Perl is called as shebang line and is the first line in a Perl program. |
02:59 | It tells where to find the Perl Interpreter. |
03:03 | Note: Though this line starts with hash symbol, it will not be considered as a single line comment by Perl. |
03:11 | Now let us look at multiline comments. |
03:13 | Multi Line: This type of comment is used |
03:17 | when user wants to comment a piece of code or to add description/usage of piece of code. |
03:25 | This type of comment starts with the symbol equal to head and ends with equal to cut. |
03:33 | Let's switch back to gedit and type the following in the comments dot pl file. |
03:39 | At the end of file, type: equal to head, press Enter. |
03:45 | print space double quote count variable is used for counting purpose double quote complete press Enter. |
03:59 | equal to cut |
04:01 | Save the file, close it and execute the Perl script. |
04:05 | On the Terminal, type: perl hyphen c comments dot pl and press Enter. |
04:13 | No syntax error. |
04:15 | So let us execute it, perl comments dot pl |
04:21 | It will show the same output as before. Count is 1. |
04:27 | It does not print the sentence “count variable is used for counting purpose”. |
04:32 | This is because we commented the portion using equal to head and equal to cut. |
04:40 | You can either use =head =cut or =begin =end. |
04:48 | These are not the special keywords used by Perl. |
04:52 | Please note, there should not be any leading or trailing space(s) before '=' (equal to sign) and after the head, cut, begin or end word. |
05:02 | Open the Terminal once again. |
05:05 | And Type - gedit commentsExample dot pl space & and press Enter. |
05:15 | Type the following commands as shown on the screen. |
05:19 | Here, I am declaring two variables firstNum and secondNum and I am assigning some values to them. |
05:28 | Then I have commented this portion here. |
05:32 | Now I added these two numbers and assign the value to a third variable named addition. |
05:39 | Next, I want to print the value using print command. |
05:44 | Save the file and execute the Perl script on the Terminal. |
05:49 | On terminal, type: perl hyphen c commentsExample dot pl, press Enter. |
05:57 | There is no syntax error. |
05:59 | So, execute the script by typing |
06:01 | perl commentsExample dot pl press Enter. |
06:07 | It will show the following output. Addition is 30. |
06:12 | This brings us to the end of this tutorial. |
06:16 | Here, we learnt to add comments in Perl. |
06:19 | Write a perl script to find square of a number. |
06:23 | Explain the functionality of the code written using single line comment & multiline Comment. |
06:30 | Watch the video available at the following link. |
06:34 | It summarizes the Spoken Tutorial project. |
06:37 | If you do not have good bandwidth, you can download and watch it. |
06:42 | The Spoken Tutorial Project Team: |
06:44 | Conducts workshops using spoken tutorials. |
06:48 | Gives certificates to those who pass an online test. |
06:51 | For more details, please write to contact at spoken hyphen tutorial dot org. |
06:58 | Spoken Tutorial Project is a part of the Talk to a Teacher project. |
07:03 | It is supported by the National Mission on Education through ICT, MHRD, Government of India. |
07:11 | More information on this mission is available at the following link. |
07:15 | Hope you enjoyed this Perl tutorial. This is Amol Brahmankar, signing off.
Thanks for joining. |