why do you export a variable ?

[Indrajit Bhagat]

why do you export a variable ?
thanks to all of those who spend few time to reply my answer.

[Patrick Wallek]

So it can be used.

[Sunny Jaisinghani · Accepted solution]

so that u can use that variable again and again without resetting the value to that variable.

[Guna_2]

Hi

I think after export a variable it will become as a environmental veriable. So ur child process also will inherits this variable.


Rgds,
Guna

[Yogeeraj_1]

hi Indrajit!

export is a command that sets environment variables for use for the entire duration of the session, unless changed. export is usually a shell built-in command.

For example, if you have 3 scripts to run simultaneously at the command line and all the 3 scripts need the same environment variables. You can just export the variables prior to the execution of script and just use it in the three scripts. This way your script becomes simpler too!

hope this helps!

Kind regards
yogeeraj

[Victor Fridyev]

If in a shell you define
varname=value
the varname is accessible in the shell only (local variable).

If you define it as
export varname=value,

the variable is accessible for the shell children as well.

HTH

[Rob Beaumont]

Indrajit,

The reason is related to 'scope' of the variable. As analogy, it can be compared (loosely though) with scope of a variable in programming language. To summerize, the 'scope' of the variable is limited to the shell (as rightly informed) and when exported the 'scope' extends upto the session.

Regards

[Indrajit Bhagat]

thank to all of you

[Bill Hassell]

As mentioned, export makes a variable useable to other processes. In your shell, each command you type such as vi or date or bdf will first create a copy of your current exportable environment and the the process runs in this environment. If you simply assign a variable but not export it, no other process started from your shell can see the variable. You can see the difference with these two commands:

set
env

The first shows your shell's total variable list but env shows only the exported variables.