Ashwini: Created page with ''''Title of script''': '''Globbing and Export Statement''' '''Author: '''FOSSEE and spoken-tutorial team '''Keywords: '''Video tutorial, Globbing, Export statement {| style…'

2013-07-26T11:22:26Z

Created page with ''''Title of script''': '''Globbing and Export Statement''' '''Author: '''FOSSEE and spoken-tutorial team '''Keywords: '''Video tutorial, Globbing, Export statement {| style…'

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'''Title of script''': '''Globbing and Export Statement'''

'''Author: '''FOSSEE and spoken-tutorial team

'''Keywords: '''Video tutorial, Globbing, Export statement

{| style="border-spacing:0;"
! <center>Visual Cue</center>
! <center>Narration</center>

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Display Slide
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Welcome to this spoken tutorial on '''Globbing and Export command'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Display Slide
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| In this tutorial, we will learn about

* '''Globbing'''
* '''export command'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Display Slide

'''Prerequisites'''

'''spoken-tutorial.org '''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| To follow this tutorial,

You should be familiar with '''Linux Operating System'''

If not, for relevant tutorials please visit '''spoken hyphen tutorial dot org'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Display Slide

'''System Requirements'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| For this tutorial I am using

* '''Ubuntu Linux 12.04''' OS and
* '''GNU Bash''' version '''4.1.10'''

'''GNU Bash '''version '''4''' or above is recommended to practise this tutorial.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Display Slide

'''Globbing'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Let us start with an introduction to '''globbing'''.

* ''Filename'' or ''pathname'' expansion carried by '''BASH''' is known as '''Globbing'''.
* '''Globbing''' recognizes and expands '''wildcards.'''
* It also interprets standard '''wildcard''' characters like

# <nowiki>* </nowiki>'''(asterix) '''and
# '''? (Question mark)'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"|
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Let us understand this with the help of an example.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Press '''Ctrl+Alt+T'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Open the terminal by pressing '''Ctrl+Alt+T''' keys.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| On '''Terminal'''>> Type '''ls *.sh'''>>''' '''Press''' Enter'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| On the '''Terminal '''type,

'''ls space asterix dot sh'''

and press '''Enter.'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| <nowiki>[Highlight]</nowiki>

<nowiki>*</nowiki>'''.sh'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| It matches all the files having '''.sh extension''' in the present directory.

'''<nowiki><<PAUSE>></nowiki>'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Highlight:

Output:

'''array.sh'''

'''Array.sh'''

'''comm.sh '''

'''data.sh'''

'''if.sh'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Here we can see that all the '''sh''' files are listed.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| On '''Terminal'''>> Type '''ls c*.sh>> '''Press''' Enter'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Next, on the '''Terminal t'''ype,

'''ls space c asterix dot sh'''

and press '''Enter.'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| <nowiki>[Highlight]</nowiki>

'''c*.sh'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| It will match all the files starting with character ''''c'''' & having '''sh''' '''extension'''.

'''<nowiki><<PAUSE>></nowiki>'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Output:

Highlight:

'''comm.sh'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| We can see that all files starting with character''' 'c'''' and extension''' sh.'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| On'''<nowiki> Terminal>> Type ls [a-c]*.sh>> </nowiki>'''Press''' Enter'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Now on the '''Terminal, '''type,

'''ls space opening square bracket a, hyphen, c closing square bracket asterix dot sh'''

and press '''Enter.'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Highlight:

'''<nowiki>[a-c]*</nowiki>'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| This will match and display the files starting with letter''' a''' or '''b '''or '''c.'''

<nowiki><<PAUSE>></nowiki>

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Output:

Highlight:

'''array.sh'''

'''comm.sh'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Observe the output.

We see a list of all files starting with character''' a '''or '''b''' or '''c.'''

And these files have '''sh''' '''extension'''.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| On '''Terminal>> '''Type '''<nowiki>ls [^a-c]* .sh>> </nowiki>'''Press''' Enter'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Next, let's go ahead and type

'''ls space opening square bracket caret symbol a hyphen c closing square bracket asterix dot sh'''

and press '''Enter.'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| '''Highlight:'''

'''<nowiki>[^a-c]*.sh</nowiki>'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| This will match all the filenames with '''extension''' '''sh.'''

But will omit those with starting character as ''''a'''' OR ''''b' '''OR ''''c' '''

<nowiki><<PAUSE>></nowiki>

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Output:

Highlight:

'''data.sh'''

'''if .sh'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Obsere the output.

You will notice that the filenames are not starting with character''' 'a'''' or ''''b' '''or''' 'c'. '''

And the '''extension '''is '''sh .'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| On''' Terminal>> '''Type'''<nowiki> ls [Aa]*.sh>> </nowiki>'''Press''' Enter'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Let's go ahead.

On the '''Terminal t'''ype,

'''ls space opening square bracket capital 'A' and lower case 'a' closing square bracket asterix dot sh'''

and press '''Enter.'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Highlight:

'''<nowiki>[Aa]*</nowiki>'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| This will match filenames starting with

upper and lower case of letter ''''A''''.''' '''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Output:

Highlight:

'''array.sh'''

'''Array.sh'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Let's see the output.

All filenames starting with upper and lower case ''''A''''''' '''and '''extension''' '''sh''' are listed.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"|
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| '''<nowiki><<PAUSE>></nowiki>'''

Now let's see the '''Export command '''in '''BASH.'''

Switch to the slides.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Display Slide

'''Export'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| * I have made some change in the language. <br/> Pls check if this is okay.In '''Bash, variables''' are '''local''' to their own '''Shell'''.
* '''Local variables''' can be used by the same '''Shell '''or by the current '''Shell'''.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Display Slide

'''Export'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| I have made some change in the language.

Pls check if this is okay.The '''Export command'''

* Exports a '''variable''' or a '''function''' to the '''environment''' of all '''child processes'''.
* Can also change a '''local''' variable to a '''global''' variable.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"|
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| We will try to understand this with an example.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Switch to '''Terminal'''>>

'''myvar=lion>> '''Press''' Enter'''

'''echo $myvar>> '''Press''' Enter'''

| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Switch to the '''Terminal '''and type,

'''myvar equal to lion'''

and press''' Enter.'''

Now type,''' '''

'''echo space dollar symbol myvar'''

and press '''Enter.'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Output:

'''lion'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| '''lion '''is printed.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Highlight '''myvar=lion'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| This was the value assigned to the '''variable myvar.'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| On '''Terminal>>'''

Type

'''/bin/bash>> '''Press '''Enter'''

| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Now, let's navigate to a new '''Shell'''.

To go to a new '''Shell''', we can either open a new '''Terminal''' or type,

'''slash bin slash bash'''

and press''' Enter.'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Type

'''echo $myvar>> '''Press''' Enter'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Now let's check the value in the variable '''myvar.'''

Type,''' '''

'''echo space dollar symbol myvar'''

and press '''Enter.'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| <nowiki>[Highlight]</nowiki>

Output:

| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| An empty line is printed.

This means that the value assigned to '''variable''' '''myvar '''was not transferred to this '''Shell'''.

Also, the variable '''myvar '''is''' local '''only to the previous '''Shell''' and not to current '''Shell'''.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Type '''exit'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| We will type '''exit '''to get back to our previous '''Shell'''.

'''<nowiki><<PAUSE>></nowiki>'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| <nowiki>[Highlight]</nowiki>
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| So, to declare variables '''globally,''' we have to use the '''export command. '''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| '''On Terminal>> '''Type '''export myvar=lion>> '''Press''' Enter>> '''

| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Let's learn how.

On the '''Terminal '''type,

'''export space myvar equal to lion'''

and press''' Enter.'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| '''Type'''

'''echo $myvar>> '''Press '''Enter'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Now type,''' '''

'''echo space dollar symbol myvar'''

and press '''Enter.'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| '''Output: lion'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| '''lion '''is displayed.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| On '''Terminal>>'''Type '''/bin/bash>> '''Press''' Enter'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Now, let's navigate to another '''Shell '''by typing, '''slash bin slash bash'''

and press''' Enter.'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Type

'''echo $myvar>> '''Press''' Enter'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Now type,''' echo space dollar symbol myvar''' and press '''Enter.'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| '''Output: lion'''
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| '''lion''' is displayed

This is because we have declared the variable '''myvar''' globally.

'''<nowiki><PAUSE></nowiki>'''

This brings us to the end of this tutorial.

Let us summarize. Come back to our slides.

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Display slide 10

Summary
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| In this tutorial we learnt,

* '''Globbing'''
* '''Export command'''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Display slide 11

Assignment
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Write a '''Bash script'''

# to do all the operations discussed under '''globbing '''in this tutorial'''. '''

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Display Slide 12
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Watch the video available at the link shown below

It summarises the Spoken Tutorial project

If you do not have good bandwidth, you can download and watch it

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Display Slide

Spoken Tutorial Workshops
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| The Spoken Tutorial Project Team

Conducts workshops using spoken tutorials

Gives certificates to those who pass an online test

For more details, please write to

contact@spoken-tutorial.org

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"| Display Slide

Acknowledgement
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| Spoken Tutorial Project is a part of the Talk to a Teacher project

It is supported by the National Mission on Education through ICT, MHRD, Government of India

More information on this Mission is available at: http://spoken-tutorial.org\NMEICT-Intro

|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:none;padding:0.097cm;"|
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding:0.097cm;"| The script has been contributed by FOSSEE and Spoken-Tutorial team.

This is Ashwini from IIT Bombay.

Thank you for joining.

|}

BASH/C2/Globbing-and-Export-statement/English - Revision history

Ashwini: Created page with ''''Title of script''': '''Globbing and Export Statement''' '''Author: '''FOSSEE and spoken-tutorial team '''Keywords: '''Video tutorial, Globbing, Export statement {| style…'