Using bash, I'm trying to read a .properties file (name=value pairs), assigning an indirect variable reference for each line in the file.
The trick is that a property's value string may contain the name of a property that occurred earlier in the file, and I want the name of the 1st property to... (5 Replies)
The construct ${#parameter} returns the number of characters in the parameter and ${!parameter} specifies an indirect variable. My question is: How do I combine these two. What I want is ${#!parameter} but this gives an error.
Of course I can use:
dummy=${!parameter}
${#dummy}
but that's a... (0 Replies)
Ummm can anybody help me with this one?
Its prob quite simple.
I bascially have a file name say J1x2x3x7.dat
Im using the file name as a variable in a bash script. Want I want to do is extract most of the file name and make it a new variable expect with say one of the number now a... (2 Replies)
Hi,
I've got a small problem.
If varible A stores "B" and Variable B stores C,
How to get the value of variable B by using only Variable A..?
I tried the following but didnt work pease help..
$ var1=vikram
$ echo $var1
vikram
$ vikram=sampath
$ echo $vikram
sampath
$ echo... (6 Replies)
Hi
I have variable A_B=alpha
also var1="A"
var2="B"
I want to retrieve the value alpha using var1 and var2 , somthing like
echo ${${var1}_${var2}} that works. Obviously this is receiving syntax
error (6 Replies)
Hello,
is there a kind soul who can answer me, does the SH support double substitution known as indirect expansion similar to BASH? The syntax for bash is ${!var}.
For instance in bash I can write something like this:
VAR="value"
REF_VAR="VAR"
echo ${!REF_VAR}
and get the "value"... (1 Reply)
I have a file with two columns of numbers (member IDs):
1 1
2 1
3 1
4 2
5 4
6 1
7 5
8 3
9 2
Think of column 1 as the referee and column 2 as the referrer.
Is there a good way to backtrack who referred who? I would like an output, for this example here to be:
1 1
2 1
3 1
4 2 1 (2 Replies)
Sometimes it is handy to protect long scripts in C++.
The following syntax works fine for simple commands:
#define SHELLSCRIPT1 "\
#/bin/bash \n\
echo \"hello\" \n\
"
int main ()
{
cout <<system(SHELLSCRIPT1);
return 0;
}
Unfortunately for there are problems for:
1d arrays:... (10 Replies)
Trying to do so
echo "111:222:333" |awk -F: '{system("export TESTO=" $2)}'But it doesn't work (2 Replies)
Discussion started by: urello
2 Replies
LEARN ABOUT DEBIAN
tree::simple::visitor::pathtoroot
Tree::Simple::Visitor::PathToRoot(3pm) User Contributed Perl Documentation Tree::Simple::Visitor::PathToRoot(3pm)NAME
Tree::Simple::Visitor::PathToRoot - A Visitor for finding the path back a Tree::Simple object's root
SYNOPSIS
use Tree::Simple::Visitor::PathToRoot;
# create an instance of our visitor
my $visitor = Tree::Simple::Visitor::PathToRoot->new();
# pass the visitor to a Tree::Simple object
$tree->accept($visitor);
# now get the accumulated path as a string
# with the '/' character as the delimiter
print $visitor->getPathAsString("/");
# include the tree's trunk in your
# output as well
$visitor->includeTrunk();
# for more complex node objects, you can specify
# a node filter which will be used to extract the
# information desired from each node
$visitor->setNodeFilter(sub {
my ($t) = @_;
return $t->getNodeValue()->description();
});
# you can also get the path back as an array
my @path = $visitor->getPath();
DESCRIPTION
Given a Tree::Simple object, this Visitor will find the path back to the tree's root node.
METHODS
new There are no arguments to the constructor the object will be in its default state. You can use the "includeTrunk" and "setNodeFilter"
methods to customize its behavior.
includeTrunk ($boolean)
Based upon the value of $boolean, this will tell the visitor to collect the trunk of the tree as well.
setNodeFilter ($filter_function)
This method accepts a CODE reference as its $filter_function argument and throws an exception if it is not a code reference. This code
reference is used to filter the tree nodes as they are collected. This can be used to customize output, or to gather specific
information from a more complex tree node. The filter function should accept a single argument, which is the current Tree::Simple
object.
visit ($tree)
This is the method that is used by Tree::Simple's "accept" method. It can also be used on its own, it requires the $tree argument to be
a Tree::Simple object (or derived from a Tree::Simple object), and will throw and exception otherwise.
getPath
This will return the collected path as an array, or in scalar context, as an array reference.
getPathAsString ($delimiter)
This will return the collected path as a string with the path elements joined by a $delimiter. If no $delimiter is specified, the
default (', ') will be used.
BUGS
None that I am aware of. Of course, if you find a bug, let me know, and I will be sure to fix it.
CODE COVERAGE
See the CODE COVERAGE section in Tree::Simple::VisitorFactory for more inforamtion.
SEE ALSO
These Visitor classes are all subclasses of Tree::Simple::Visitor, which can be found in the Tree::Simple module, you should refer to that
module for more information.
AUTHOR
stevan little, <stevan@iinteractive.com>
COPYRIGHT AND LICENSE
Copyright 2004, 2005 by Infinity Interactive, Inc.
<http://www.iinteractive.com>
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
perl v5.10.1 2005-07-14 Tree::Simple::Visitor::PathToRoot(3pm)