Re: manipulating PS1 in sh

2006-10-30 <1162217283.682259.169560@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
EdStevens wrote:

Radoulov, Dimitre wrote:
Trying to set PS1 to reflect the current value of a user environment
variable, when running in sh.

Most of my systems I am running in ksh, and my PS is set as follows:

export PS1=`hostname`'.''$ORACLE_SID> '

so that my prompt always shows the current value of $ORACLE_SID. But
it appears that this syntax doesn't yeild the same results with sh.
There, instead of returning the value of $ORACLE_SID, it simply returns
the literal "$ORACLE_SID".
[...]

$ PS1=`hostname`'.''$ORACLE_SID> '
xxx.ora10gr2> sh
xxx.$ORACLE_SID> PS1="`hostname`.$ORACLE_SID>"
xxx.ora10gr2>


Regards
Dimitre

Which returns the LITERAL "$ORACLE_SID". I need the VALUE of the
ORACLE_SID variable, like this:

$> ORACLE_SID=db01
$> echo $ORACLE_SID
$> db01
$> PS1= "`hostname`'.'?????'>'
db01>
db01> ORACLE_SID=db02
db02> echo $ORACLE_SID
db02> db02
echo "$ORACLE_SID"
db02

Now, of course - it still won't change when you update it... you'd
probably need to make an alias to do that.

PS1_SRC='`hostname`.$ORACLE_SID>'
alias ps1upd=eval\ echo\ PS1=\\\"\\\'\$PS1_SRC\\\'\\\"
# Has to expand $PS1_SRC in double quotes outside the eval while
# putting it in single quotes inside the eval.

Actually, from my understanding of quoting rules this shouldn't work -
and I don't have a real sh to test it on, so if it doesn't work let me
know and i'll figure something else out. Then again it might work - i
don't really understand eval so this might be some obscure case that
makes it work.

(btw - you would not believe how many tries it took to get the quoting
right on that.) now call ps1upd whenever the hostname or ORACLE_SID
changes, feel free to add other stuff, etc. You can put anything in
PS1_SRC that you could put in a ksh prompt.
.

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