Difference between revisions of "BASH/C2/Globbing-and-Export-statement/English-timed"

!Time  

!Narration  

|Welcome to this spoken tutorial on '''Globbing and Export command'''

|In this tutorial, we will learn about

|* '''Globbing'''

 

|* '''export command'''

 

| To follow this tutorial, You should be familiar with '''Linux Operating System'''

|If not, for relevant tutorials please visit our  website which is are shown.

|For this tutorial I am using  

|* '''Ubuntu Linux 12.04''' OS and  

|* '''GNU Bash''' version '''4.1.10'''

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

|* ''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)'''

 

 

|Open the terminal window by pressing '''Ctrl+Alt''' and '''T''' keys simultaneously on your keyboard.

|On the '''Terminal ''' type,'''ls space asterix dot sh''' press '''Enter.'''

|It matches all the files having '''.sh extension''' in the present directory.

 

|Here we can see that all the '''sh''' files are listed.

|Let me clear the prompt,Now type, '''ls space s asterix dot sh''' press '''Enter.'''

| We can see that '''s asterix dot sh''' matches all the files starting with character '''s''' and having '''sh as  extension.  

| Lets move on ,

| Now '''type, '''ls space opening square bracket a hyphen c closing square bracket asterix dot sh''' press '''Enter.'''

| This will match and display the files starting with letter ''' a''' or '''b '''or '''c.'''

 

| Observe the output.

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

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

|Now, let's go ahead and type '''ls space opening square bracket caret sign a hyphen c closing square bracket asterix dot sh''' press '''Enter.'''

| This will match all the filenames with '''extension''' '''sh.'''

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

 

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

|Let me clear the prompt,

| Now type, '''ls space opening square bracket capital 'A'  small 'a' closing square bracket asterix sign dot sh''' press '''Enter.'''

| This will match filenames starting with upper and lower case of letter ''''A''''.

| See the output.All filenames starting with upper and lower case ''''A''' and extension '''sh''' are listed.

| Switch to the slides.

|* '''Local variables''' can be used by same '''Shell ''' or by the current '''Shell'''.  

| '''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.

| Switch to the '''Terminal ''' type, '''myvar equal to sign lion''' press''' Enter.'''

 

| Now type, '''echo space dollar sign myvar''' press '''Enter.'''

| To go to a new '''Shell''', we can either open a new '''Terminal''' or type, '''slash bin slash bash''' press''' Enter.'''

 

| Now let's check the value in the variable '''myvar.'''

| Type, '''echo space dollar sign myvar''' press '''Enter.'''

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

| So, to declare variables '''globally,''' we have to use the '''export command. '''

| Type, '''export space myvar equal to sign lion ''' press''' Enter.'''

| Now type, '''echo space dollar sign myvar''' press '''Enter.'''

| Let's navigate to another '''Shell''', type, '''slash bin slash bash''' press ''' Enter.'''

| Let me clear the prompt.

|  Now type,'''echo space dollar sign myvar'''.  

| This is because we have declared the variable '''myvar''' globally using the export command.

| Let us summarize. Come back to our slides.

|  In this tutorial we learnt,

| * '''Globbing'''

 

| 06:42

|* '''Export command'''

| As an assignment.

 

| Write a '''Bash script''' to do all the operations discussed under '''globbing.'''

| 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

|The Spoken Tutorial Project Team

| Conducts workshops using spoken tutorials  

| Gives certificates to those who pass an online test  

|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 the link shown below.

| This is Ashwini from IIT Bombay Signning off.