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Which assignment syntax to use when?

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# 1  
Old 06-19-2013
Which assignment syntax to use when?
Hi,

Lately, I have seen 2-3 variable assignment commands - set, setenv, export. What is the difference between them? Which one to use when? Really appreciate for the help...

regards,
juzz4fun
# 2  
Old 06-19-2013
I suggest you read the man page of the shell which you didin't tell us any specifics about.

"export" is not an assignment, it just marks an already assigned vaiabl for export when a new shell environment is invoked.

"setenv" is a csh assignment command.

"set" in most cases (with the exception of "set --", which deletes positional variables in Bourne-shell descendants and "set -A" in ksh) just lists all the assigned variables, not assigns them.

I hope this helps.

bakunin
This User Gave Thanks to bakunin For This Post:
juzz4fun
# 3  
Old 06-19-2013
sh, bash and ksh sets variables with just the "=" sign (i.e., aa=boo) while csh and tcsh sets variables with set at the beginning of the line (i.e., set aa = boo) ...

variables are usually local to the subshell the script/user is working in ... if a variable is being set by one shell and needed to be used in another shell, the variable must be exported or shared from the local shell and imported by the other shells ...

sh, bash, and ksh uses export while csh and tcsh uses setenv to share the variables from the local shell ...


-------------

forgot about the info on set that bakunin mentioned ... guess i need to get reading again ...
This User Gave Thanks to Just Ice For This Post:
juzz4fun
# 4  
Old 06-19-2013
Thanks a ton, JustIce and bakunin ... you are superb !
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