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AIX 6.1, setting env vars

Posted on 2011-09-21
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Last Modified: 2013-11-17
I am trying to set an env var in AIX

I set the variable TEST, but it does not show up as being set

$ echo $TEST

$ set TEST=one
$
$ set
AUTHSTATE=files
........
_=TEST=one
$
$ echo $TEST

$ echo $PATH
/opt/IBM/mqsi/7.0/jre16/bin:/opt/IBM/mqsi/7.0/bin:/usr/bin:/etc:/usr/sbin:/usr/ucb:/var/mqm/bin:/usr/bin/X11:/sbin:.

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What does this line mean:

_=TEST=one

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What am I doing wrong?

Thanks
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Question by:Los Angeles1
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4 Comments
 
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Accepted Solution

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woolmilkporc earned 500 total points
ID: 36575462
Hi,

the variable "_"  indicates the value of the parameter of the last set command issued.

It doesn't have any meaning for the actual environment (in a user's perspective).

Explanation: set is meant  to set positional parameters.

set TEST=one

will set the positional variable $1 to "TEST=one" (and $_, for that matter).

Check this with "echo $1"  and also "echo $_"

A special case is "set" when issued without any arguments. This displays the names and values of all KornShell variables, sorted by name.

Don't use "set" for defining variables.

Use just

VAR=value

for the current shell and

export VAR=value

for the current shell and its subshells (e.g. scripts called from the current shell).


wmp
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LVL 68

Expert Comment

by:woolmilkporc
ID: 36575500
Try this to make it (perhaps) a bit clearer:


set A B C

echo $1
echo $2
echo $3

echo $_

OK?


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Author Closing Comment

by:Los Angeles1
ID: 36575567
Thanks, that was perfect.  Everything is working great, and I seet the $1, etc
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LVL 68

Expert Comment

by:woolmilkporc
ID: 36575577
>> doesn't have any meaning ... << 

It depends.

A net trick is using $_ to find the last field in a line.

Assume that you want to know the value of the 15 minute load average:

set $(uptime); echo $_

Not very common, but ...
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