01-07-2013
I don't think there is a super-fast way to handle 50G of data.
Taking advantage of a database index sounds as good a way as any, a proper DB is designed to duplicate-check data larger than memory.
10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
i have a file with some 1000 entries it will contain entries like
1000,ram
2000,pankaj
1001,rahim
1000,ram
2532,govind
2000,pankaj
3000,venkat
2532,govind
what i want is i want to extract only the distinct rows from this file
so my output should contain only
1000,ram... (2 Replies)
Discussion started by: trichyselva
2 Replies
2. UNIX for Dummies Questions & Answers
hey all,
I need some help.
I have a text file with names in it.
My target is that if a particular pattern exists in that file more than once..then i want to rename all the occurences of that pattern by alternate patterns..
for e.g if i have PATTERN occuring 5 times then i want to... (3 Replies)
Discussion started by: ashisharora
3 Replies
3. Shell Programming and Scripting
I have a log file with posts looking like this:
--
Messages can be delivered by different systems at different times. The id number is used to sort out duplicate messages. What I need is to strip the arrival time from each post, sort posts by id number, and reattach arrival time to respective... (2 Replies)
Discussion started by: Ilja
2 Replies
4. Shell Programming and Scripting
Hi Experts,
Please check the following new requirement. I got data like the following in a file.
FILE_HEADER
01cbbfde7898410| 3477945| home| 1
01cbc275d2c122| 3478234| WORK| 1
01cbbe4362743da| 3496386| Rich Spare| 1
01cbc275d2c122| 3478234| WORK| 1
This is pipe separated file with... (3 Replies)
Discussion started by: tinufarid
3 Replies
5. Shell Programming and Scripting
Hi,
I have a file that I want to change the format of. It is a large file in rows but I want it to be comma separated (comma then a space).
The current file looks like this:
HI, Joe, Bob, Jack, Jack
After I would want to remove any duplicates so it would look like this:
HI, Joe,... (2 Replies)
Discussion started by: kylle345
2 Replies
6. HP-UX
I have 2 files; one file (say, details.txt) contains the details of employees and another file (say, emp.txt) has some selected employee names. I am extracting employee details from details.txt by using emp.txt and the corresponding code is:
while read line
do
emp_name=`echo $line`
grep -e... (7 Replies)
Discussion started by: arb_1984
7 Replies
7. UNIX for Dummies Questions & Answers
Hi All,
I am merging files coming from 2 different systems ,while doing that I am getting duplicates entries in the merged file
I,01,000131,764,2,4.00
I,01,000131,765,2,4.00
I,01,000131,772,2,4.00
I,01,000131,773,2,4.00
I,01,000168,762,2,2.00
I,01,000168,763,2,2.00... (5 Replies)
Discussion started by: Sri3001
5 Replies
8. Shell Programming and Scripting
i hav two files like
i want to remove/delete all the duplicate lines in file2 which are viz unix,unix2,unix3 (2 Replies)
Discussion started by: sagar_1986
2 Replies
9. Shell Programming and Scripting
i hav two files like
i want to remove/delete all the duplicate lines in file2 which are viz unix,unix2,unix3.I have tried previous post also,but in that complete line must be similar.In this case i have to verify first column only regardless what is the content in succeeding columns. (3 Replies)
Discussion started by: sagar_1986
3 Replies
10. Shell Programming and Scripting
I am trying to remove whitespaces from a file containing sample data as:
457 <EOFD> Mar 1 2007 12:00:00:000AM <EOFD> Mar 31 2007 12:00:00:000AM <EOFD> system <EORD> 458 <EOFD> Mar 1 2007 12:00:00:000AM<EOFD>agf <EOFD> Apr 20 2007 9:10:56:036PM <EOFD> prodiws<EORD> . Basically these... (11 Replies)
Discussion started by: amvip
11 Replies
LEARN ABOUT PHP
sqlite_popen
SQLITE_POPEN(3) SQLITE_POPEN(3)
sqlite_popen - Opens a persistent handle to an SQLite database and create the database if it does not exist
SYNOPSIS
resource sqlite_popen (string $filename, [int $mode = 0666], [string &$error_message])
DESCRIPTION
This function behaves identically to sqlite_open(3) except that is uses the persistent resource mechanism of PHP. For information about
the meaning of the parameters, read the sqlite_open(3) manual page.
sqlite_popen(3) will first check to see if a persistent handle has already been opened for the given $filename. If it finds one, it returns
that handle to your script, otherwise it opens a fresh handle to the database.
The benefit of this approach is that you don't incur the performance cost of re-reading the database and index schema on each page hit
served by persistent web server SAPI's (any SAPI except for regular CGI or CLI).
Note
If you use persistent handles and have the database updated by a background process (perhaps via a crontab), and that process re-
creates the database by overwriting it (either by unlinking and rebuilding, or moving the updated version to replace the current
version), you may experience undefined behaviour when a persistent handle on the old version of the database is recycled.
To avoid this situation, have your background processes open the same database file and perform their updates in a transaction.
PARAMETERS
o $filename
- The filename of the SQLite database. If the file does not exist, SQLite will attempt to create it. PHP must have write permis-
sions to the file if data is inserted, the database schema is modified or to create the database if it does not exist.
o $mode
- The mode of the file. Intended to be used to open the database in read-only mode. Presently, this parameter is ignored by the
sqlite library. The default value for mode is the octal value 0666 and this is the recommended value.
o $error_message
- Passed by reference and is set to hold a descriptive error message explaining why the database could not be opened if there was
an error.
RETURN VALUES
Returns a resource (database handle) on success, FALSE on error.
SEE ALSO
sqlite_open(3), sqlite_close(3), sqlite_factory(3).
PHP Documentation Group SQLITE_POPEN(3)