01-07-2009
Quote:
Originally Posted by
cbkihong
Wow. Amazing!!!! I haven't seen people test primes like that (but I guess it is not an efficient way to do so)!
It converts the number passed from the command line into a string consisting of a sequence of that number of '1's (1 x shift). Then try to divide that sequence into an integral number of equally-sized chunks, with each consisting of at least 2 '1's (/^(11+)\1+$/). If we cannot divide so, then it will be a prime (hence with the !~ operator)!
I will not have thought of tricks like that.
Hi,
please tell me how to master your level of experience in reading shell scripts ?
Frankly speaking I would love parser application, generating
human HowItWorks output for any such script on input.
Darius
10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
I'm writing a script to automate some post-install tasks on RHEL4 servers.
I need the following code to insert an 'A' in the middle of a string, then replace the string in a file. I know I can use sed to do this, but I'd like to use perl's in place edit so I don't have to write to a temp file,... (1 Reply)
Discussion started by: Xek
1 Replies
2. Shell Programming and Scripting
In a ~4GB file there are lines like,
13.13.4.3 Googe.com - Jan/23/2011:00:00:00 +0000 "URL Google HTTP/1.1" 45 56 208 - "http://www.gogle.com/webhp?hl=en&tab=nw#hl=en&source=hp&biw=1366&bih=667&q=hello&aq=f&aqi=&aql=&oq=&fp=c432485467934a89" ".Net; Fox" -
13.145.3.3 Goge.com -... (3 Replies)
Discussion started by: gameboy87
3 Replies
3. Shell Programming and Scripting
Thanks for giving your time and effort to answer questions and helping newbies like me understand awk.
I have a huge file, millions of lines, so perl takes quite a bit of time, I'd like to convert these perl one liners to awk.
Basically I'd like all lines with ISA sandwiched between... (9 Replies)
Discussion started by: verge
9 Replies
4. Shell Programming and Scripting
can someone help me translate the following command, from:
/usr/bin/awk "/^$TOFDAYM $TOFDAYD /,0" $LOGFILE
to something like
perl -e .....
basically, i want to use perl to do awk functions within a shell script. i want to do the above awk, using perl.
any suggestions? (9 Replies)
Discussion started by: SkySmart
9 Replies
5. Shell Programming and Scripting
hello,
I want to replace awk with a perl one liner in unix.
i use in awk REGEX and FS ( field separator) because
awk syntaxes in different unix os versions have not the same behaviour.
Awk, Nawk and GNU Awk Cheat Sheet - good coders code, great reuse
i have a file named "file" and want... (5 Replies)
Discussion started by: bora99
5 Replies
6. UNIX for Dummies Questions & Answers
Not quite a unix question but problem in a perl command. Taking a chance if someone knows about the error
cat 1
a b c d
perl -p -e 's/a/b/g' 1
b b c d
What is the problem here??
perl -p -i -e 's/a/b/g' 1
Can't remove 1: Text file busy, skipping file. (2 Replies)
Discussion started by: analyst
2 Replies
7. Shell Programming and Scripting
Hi all,
I need a Perl one liner which prints a newline into a .txt file, only where the line starts with "/mediawiki-1.19.0/". It should add the newline to the line before.
My problem is, when I try to realize this (with my little knowledge :rolleyes: ) i come to the point where the // are... (4 Replies)
Discussion started by: Mr.Smith
4 Replies
8. Shell Programming and Scripting
hi,
I am using PERL one liner for oracle database connection as :
$PERL -e "use DBI; DBI->connect(qw(DBI:Oracle:SID user passwd));"
is there a way to append select statement to this connection ? i.e. DB connection and select stmt in one line ?
how to do sysdba connection using one lines... (1 Reply)
Discussion started by: talashil
1 Replies
9. Shell Programming and Scripting
Greetings fellow scripters.
I find myself editing multiple files, sometimes with the same bits of information. My bash script, a changelog, and a plist file (OS X). Once I realized this, I thought why not script part of this process (and so it begins). In any case, I've solved several of the... (1 Reply)
Discussion started by: reid
1 Replies
10. Shell Programming and Scripting
Hi
I have an inherited perl script that extracts the first three octets of an IP Address using a combination of split() against a dot and then builds it all back together again, its a whole block of code to do this
I wondered if anyone had a one liner in their arsenal to extract the first... (7 Replies)
Discussion started by: hcclnoodles
7 Replies
factor(1) General Commands Manual factor(1)
NAME
factor, primes - factor a number, generate large primes
SYNOPSIS
[number]
[start[stop]]
DESCRIPTION
If no arguments are provided on the command line, waits for a number to be typed in. If a positive number is typed, it factors the number
and print its prime factors; each one is printed the proper number of times. It then waits for another number. exits if it encounters a
zero or any non-numeric character.
If an argument is provided on the command line, factors the number as above, then exits.
Maximum time to factor is proportional to sqrt(n) and occurs when n is prime or the square of a prime.
The largest number that can be dealt with by is 1.0e14.
prints prime numbers between a lower and upper bound. If no arguments are provided on the command line, waits for two numbers to be typed
in. The first number is interpreted as the lower bound; the second as the upper bound. All prime numbers in the resulting inclusive range
are printed.
If start is specified, all primes greater than or equal to start are printed. If both start and stop are given, all primes occurring in
the inclusive range start through stop are printed.
start and stop values must be integers represented as long integers.
If the stop value is omitted in either case, runs either until overflow occurs or until it is stopped by typing the interrupt character.
The largest number that can be dealt with by is 2,147,483,647.
DIAGNOSTICS
Both commands print when the input is out of range, illegal characters are encountered, or when start is greater than stop.
EXAMPLES
Print the prime factorization for the number 12:
Print all prime numbers between 0 and 20:
factor(1)