You either can't or won't tell me what the purpose of your program is. Nobody writes a program to "substitute in a variable", presumably that program has some actual use to you.
Fine, I'll do what I can without it.
You are doing it exactly backwards, which is why you are having so many problems. Set the variables first. Then make your query, letting it substitute the variables right then and there. That is the way variables are supposed to work. You'll get exactly what you want, quotes intact.
If possible, use it directly instead of storing it in a variable -- 30 lines is a lot to put in one variable, and you want to avoid splitting and accidental substitution anyway. You can use a here-document to stream something into a program, variables will substitute inside it:
Code:
databaseprogram <<EOF
Select '$ENV',t1.field1,t2.field2
from $table1 t1,$table2 t2
where t1.field1='$var1'
and t2.field1='$var2'
EOF
Last edited by Corona688; 08-09-2012 at 06:49 PM..
Hi
I have a variable which is a path ie:
UBERROR=/cobwrk/mchr/prodsup/ub/wrk/../error
is there anyway I can get the output of an echo to read:
#echo $UBERROR
/cobwrk/mchr/prodsup/ub/error
instead of
#echo $UBERROR
/cobwrk/mchr/prodsup/ub/wrk/../error
Many thanks! (2 Replies)
I would like to know how to pass a variable inside a variable to a function.
sample code below
--------------
for x in 1 9
do
check_null $C$x ##call function to check if the value is null
if
then
echo "line number:$var_cnt,... (2 Replies)
Hi Gurus
I have a file called /tmp/CMDB which looks like this
serial: 0623AN1208
hostname: server1
model: x4100
assetID: 1234
I am writing a for loop that will go through this file line by line creating a variable of itself. Using the first iteration of the loop (i.e. the first line) as... (6 Replies)
Hi,
I am trying to do the following thing
var='date'
$var
Above command substitutes date for and in turn runs the date command and i am getting the todays date value.
I am trying to do the same thing as following, but facing some problems,
unique_host_pro="sed -e ' /#/d'... (3 Replies)
Hi there, i think im getting myself a little confused and need some help :wall:
I am reading in a bunch of variables to my script from an external file and need to validate that a value has been set for each
so if you can imagine, the user is required to pass in 4 values... (3 Replies)
I am tyring to resolve an environment variable that is part of a string I selected from our database.
Simply put, I want cd to this folder before checking if a file exists.
The variable $in_loc has the value '$PS_HOME/int/VSP' where $PS_HOME is the environment variable.
I am using cd... (6 Replies)
Hi All,
I have below variable,
xyz=\$AI_XFR
Now, if you will run the below command
=> echo $xyz
$AI_XFR
It is returning hardcoded string value.
Whereas in environment, there is value in it. Like below:
=> echo $AI_XFR
/home/aditya/sandbox/xfr/
I need to resolve this... (4 Replies)
My script
----------
for i in `cat n`;do
export k=`echo "CSN: "$i` //combining CSN: and value from n
echo "$k"
awk ''{print "CSN: "$0;}'{_=29}_&&_--' file1|tail -1 >> file2
done
In the above script i cannot able to resolve $k in awk command
file n contains
------------
0000
1111
2222... (2 Replies)
Hi guys,
I have a file "abc.dat" in below format:
FILE_PATH||||$F_PATH
TABLE_LIST||||a|b|c
SYST_NM||||${SRC_SYST}
Now I am trying to read the above file and want to print the value for above dollar variables F_PATH and SRC_SYST. The problem is it's reading the dollar variables as... (5 Replies)
Discussion started by: abcabc1103
5 Replies
LEARN ABOUT CENTOS
readonly::xs
XS(3) User Contributed Perl Documentation XS(3)NAME
Readonly::XS - Companion module for Readonly.pm, to speed up read-only scalar variables.
VERSION
This document describes version 1.05 of Readonly::XS, February 24, 2009.
SYNOPSIS
Install this module, but do not use it.
DESCRIPTION
The Readonly module (q.v.) is an effective way to create non-modifiable variables. However, it's relatively slow.
The reason it's slow is that is implements the read-only-ness of variables via tied objects. This mechanism is inherently slow. Perl
simply has to do a lot of work under the hood to make tied variables work.
This module corrects the speed problem, at least with respect to scalar variables. When Readonly::XS is installed, Readonly uses it to
access the internals of scalar variables. Instead of creating a scalar variable object and tying it, Readonly simply flips the SvREADONLY
bit in the scalar's FLAGS structure.
Readonly arrays and hashes are not sped up by this, since the SvREADONLY flag only works for scalars. Arrays and hashes always use the tie
interface.
Why implement this as a separate module? Because not everyone can use XS. Not everyone has a C compiler. Also, installations with a
statically-linked perl may not want to recompile their perl binary just for this module. Rather than render Readonly.pm useless for
these people, the XS portion was put into a separate module.
Programs that you write do not need to know whether Readonly::XS is installed or not. They should just "use Readonly" and let Readonly
worry about whether or not it can use XS. If the Readonly::XS is present, Readonly will be faster. If not, it won't. Either way, it will
still work, and your code will not have to change.
Your program can check whether Readonly.pm is using XS or not by examining the $Readonly::XSokay variable. It will be true if the XS
module was found and is being used. Please do not change this variable.
EXPORTS
None.
SEE ALSO
Readonly.pm
AUTHOR / COPYRIGHT
Eric Roode, roode@cpan.org
Copyright (c) 2003-2009 by Eric J. Roode. All Rights Reserved. This module is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
To avoid my spam filter, please include "Perl", "module", or this module's name in the message's subject line, and/or GPG-sign your
message.
perl v5.16.3 2009-02-24 XS(3)