The newer shells, ksh and bash, have a lot of syntactical elements that are easily confused with one another.
The "Pattern Substitution Operators" syntax:
can have a number of substitution operations with #, %, etc. They use the meta-characters, *, [], and ? -- page 123 ff, Learning the Korn Shell, 2nd Edition ("LTKS").
The "Patterns and Regular Expression" syntax uses:
which correspond to the usual syntax we find in grep, etc:
These patterns could be used within double brackets, for example:
but not with string operator syntax (as far as I know) -- page 113 ff, 144 ff.
The ksh I use (pdksh, even on Solaris) notes a bad substitution for what I think is the right thing, but bash does it correctly in my opinion. Here's an example:
Producing:
Perhaps someone will stop by with a better explanation or a better suggestion ... cheers, drl
Hi,
I have file 1.txt with following entries as shown:
0152364|134444|10.20.30.40|015236433
0233654|122555|10.20.30.50|023365433
**
**
**
In file 2.txt I have the following entries as shown:
0152364|134444|10.20.30.40|015236433
0233654|122555|10.20.30.50|023365433... (4 Replies)
Hi all,
I'm looking for some help. I have a file (very long) that is organized like below:
>Cluster 0
0 283nt, >01_FRYJ6ZM12HMXZS... at +/99%
1 279nt, >01_FRYJ6ZM12HN12A... at +/99%
2 281nt, >01_FRYJ6ZM12HM4TS... at +/99%
3 283nt, >01_FRYJ6ZM12HM946... at +/99%
4 279nt,... (4 Replies)
All,
I have the following file:
--------------------------------------
#
# /etc/pam.d/common-password - password-related modules common to all services
#
# This file is included from other service-specific PAM config files,
# and should contain a list of modules that define the services... (2 Replies)
I figured this would be simple, but I am stuck.
Variable longpath="/dir1/dir2/dir3/filename.stuff.morestuff.garbage"
I want to end up with just "filename.extra.moreextra". So, I want to get rid of the path and .garbage
I want to do this with just ksh internals. So, no sed,grep,awk,expr,... (4 Replies)
Hi,
I am trying to get a result out of this but fails please help. Have two files /tmp/1 & /tmp/hosts.
/tmp/1
IP=123.456.789.01
WAS_HOSTNAME=abcdefgh.was.tb.dsdc
/tmp/hosts
123.456.789.01
I want this result in /tmp/hosts if hostname is already there dont want duplicate entry.
... (5 Replies)
'Hi
I'm using the following code to extract the lines(and redirect them to a txt file) after the pattern match. But the output is inclusive of the line with pattern match.
Which option is to be used to exclude the line containing the pattern?
sed -n '/Conn.*User/,$p' > consumers.txt (11 Replies)
The sample file:
dept1: user1,user2,user3
dept2: user4,user5,user6
dept3: user7,user8,user9
I want to match by '/^dept2.*/' but don't want to have substring 'dept2:' in output. How to compose such regex? (8 Replies)
Hi all!
Thanks for taking the time to view this!
I want to grep out all lines of a file that starts with pattern 1 but also does not match with the second pattern.
Example:
Drink a soda
Eat a banana
Eat multiple bananas
Drink an apple juice
Eat an apple
Eat multiple apples
I... (8 Replies)
Hi
I need to do a patten match between files .
I am new to shell scripting and have come up with this so far. It take 50 seconds to process files of 2mb size . I need to tune this code as file size will be around 50mb and need to save time.
Main issue is that I need to search the pattern from... (2 Replies)
Discussion started by: nitin_daharwal
2 Replies
LEARN ABOUT DEBIAN
devel::refcount
Devel::Refcount(3pm) User Contributed Perl Documentation Devel::Refcount(3pm)NAME
"Devel::Refcount" - obtain the REFCNT value of a referent
SYNOPSIS
use Devel::Refcount qw( refcount );
my $anon = [];
print "Anon ARRAY $anon has " . refcount($anon) . " reference
";
my $otherref = $anon;
print "Anon ARRAY $anon now has " . refcount($anon) . " references
";
DESCRIPTION
This module provides a single function which obtains the reference count of the object being pointed to by the passed reference value.
FUNCTIONS
$count = refcount($ref)
Returns the reference count of the object being pointed to by $ref.
COMPARISON WITH SvREFCNT
This function differs from "Devel::Peek::SvREFCNT" in that SvREFCNT() gives the reference count of the SV object itself that it is passed,
whereas refcount() gives the count of the object being pointed to. This allows it to give the count of any referent (i.e. ARRAY, HASH,
CODE, GLOB and Regexp types) as well.
Consider the following example program:
use Devel::Peek qw( SvREFCNT );
use Devel::Refcount qw( refcount );
sub printcount
{
my $name = shift;
printf "%30s has SvREFCNT=%d, refcount=%d
",
$name, SvREFCNT($_[0]), refcount($_[0]);
}
my $var = [];
printcount 'Initially, $var', $var;
my $othervar = $var;
printcount 'Before CODE ref, $var', $var;
printcount '$othervar', $othervar;
my $code = sub { undef $var };
printcount 'After CODE ref, $var', $var;
printcount '$othervar', $othervar;
This produces the output
Initially, $var has SvREFCNT=1, refcount=1
Before CODE ref, $var has SvREFCNT=1, refcount=2
$othervar has SvREFCNT=1, refcount=2
After CODE ref, $var has SvREFCNT=2, refcount=2
$othervar has SvREFCNT=1, refcount=2
Here, we see that SvREFCNT() counts the number of references to the SV object passed in as the scalar value - the $var or $othervar
respectively, whereas refcount() counts the number of reference values that point to the referent object - the anonymous ARRAY in this
case.
Before the CODE reference is constructed, both $var and $othervar have SvREFCNT() of 1, as they exist only in the current lexical pad. The
anonymous ARRAY has a refcount() of 2, because both $var and $othervar store a reference to it.
After the CODE reference is constructed, the $var variable now has an SvREFCNT() of 2, because it also appears in the lexical pad for the
new anonymous CODE block.
PURE-PERL FALLBACK
An XS implementation of this function is provided, and is used by default. If the XS library cannot be loaded, a fallback implementation in
pure perl using the "B" module is used instead. This will behave identically, but is much slower.
Rate pp xs
pp 225985/s -- -66%
xs 669570/s 196% --
SEE ALSO
o Test::Refcount - assert reference counts on objects
AUTHOR
Paul Evans <leonerd@leonerd.org.uk>
perl v5.14.2 2011-11-15 Devel::Refcount(3pm)