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Linux bash script basic string manipulation

  
How to concatenate strings in bash script?

Example: Jan 1 2015

If you just need to take the first letter or the first character:

------------------------------------------------------------ 
stringvar="Jan 1 2015"

first_letter_only=${stringvar:0:1}

echo "$first_letter_only"

#result would be "J"
------------------------------------------------------------

${stringvar:0:1} - "0" tells bash to start cutting the string at zero position
                           - "1" means get only 1 character

To get 2015 from the same string above:
------------------------------------------------------------
stringvar="Jan 1 2015"

get_year_only=${stringvar:6:4}

echo "$get_year_only"

#result would be "2015"
------------------------------------------------------------

How to get the position of the string?

Count from the first character start with “0” zero, up to the last character on the string include spaces, symbols or whatever character is on the string.

When assigning variable or string don't put a space from the "=" equals sign to the string.

Like: stringvar= "Jan 1 2015"  -- this would result to error


Observer also the curvely braces when there is a process involved and the result is assigned to the variable.

get_year_only=$(stringvar:6:4) - open and close parenthesis is wrong


This is the basic and simple stuff to manipulate string on bash script.

As your mileage vary through the years of course, things will get exciting always. But if you are just beginning to grasp the world of bash scripting then start the basic right and understand it thoroughly, then the next will be easy.


Cheers.. Enjoy.. till net time….

Linux Android App cheat sheet:
https://play.google.com/store/apps/details?id=com.LinuxMobileKit

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