Sponsored Content
Top Forums Shell Programming and Scripting Bash - array loop performance Post 302919565 by math4 on Thursday 2nd of October 2014 06:14:16 AM
Old 10-02-2014
I have rewrite the function in perl: wow, very fast!
I like perl seem easy to understand.
If someone is interested...

Code:
sub decrypt {
    my ($f, $key) = @_;
    my $s;
    {
      local *FH;
      open FH, "$f" or die $!;
      -f FH and sysread FH, $s, -s FH;
    }
    my $n=length($s);
    my $k1=11+($key % 233); my $k2= 7+($key % 239);
    my $k3= 5+($key % 241); my $k4= 3+($key % 251);
    my @sn = unpack("C*", $s);   
  # debug: print "@sn\n";
    my $i=0;
    for ($i=0; $i<($n-2); $i++) { $sn[$i]=(($sn[$i] ^ $sn[$i+2] ^ ($k4 * $sn[$i+1])) % 256); }
    for ($i=($n-1); $i>1; $i--) { $sn[$i]=(($sn[$i] ^ $sn[$i-2] ^ ($k3 * $sn[$i-1])) % 256); }
    for ($i=0; $i<($n-1); $i++) { $sn[$i]=(($sn[$i] ^ $sn[$i+1] ^ ($k2 * $sn[$i+1])) % 256); }
    for ($i=($n-1); $i>0; $i--) { $sn[$i]=(($sn[$i] ^ $sn[$i-1] ^ ($k1 * $sn[$i-1])) % 256); }
    $s=""; for ($i=0; $i<$n; $i++) { $s.=chr( $sn[$i] ); }  
}

 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Using variables created sequentially in a loop while still inside of the loop [bash]

I'm trying to understand if it's possible to create a set of variables that are numbered based on another variable (using eval) in a loop, and then call on it before the loop ends. As an example I've written a script called question (The fist command is to show what is the contents of the... (2 Replies)
Discussion started by: DeCoTwc
2 Replies

2. Shell Programming and Scripting

problem access array outside of loop in bash

Below is a test script I was trying to use so that I could understand why the logic was not working in a larger script. While accessing and printing array data inside the while loop, everything is fine. Outside the loop, i guess everything is null?? The for loop that is meant to cycle... (4 Replies)
Discussion started by: adlmostwanted
4 Replies

3. Shell Programming and Scripting

Array Variable being Assigned Values in Loop, But Gone when Loop Completes???

Hello All, Maybe I'm Missing something here but I have NOOO idea what the heck is going on with this....? I have a Variable that contains a PATTERN of what I'm considering "Illegal Characters". So what I'm doing is looping through a string containing some of these "Illegal Characters". Now... (5 Replies)
Discussion started by: mrm5102
5 Replies

4. Shell Programming and Scripting

Bash 3.2 - Array / Regex - IF 3rd member in array ends in 5 digits then do somthing...

Trying to do some control flow parsing based on the index postion of an array member. Here is the pseudo code I am trying to write in (preferably in pure bash) where possible. I am thinking regex with do the trick, but need a little help. pesudo code if == ENDSINFIVEINTS ]]; then do... (4 Replies)
Discussion started by: briandanielz
4 Replies

5. Shell Programming and Scripting

awk loop using array:wish to store array values from loop for use outside loop

Here's my code: awk -F '' 'NR==FNR { if (/time/ && $5>10) A=$2" "$3":"$4":"($5-01) else if (/time/ && $5<01) A=$2" "$3":"$4-01":"(59-$5) else if (/time/ && $5<=10) A=$2" "$3":"$4":0"($5-01) else if (/close/) { B=0 n1=n2; ... (2 Replies)
Discussion started by: klane
2 Replies

6. UNIX for Advanced & Expert Users

How to test RAID10 array performance [Debian Wheezy]?

I have created a RAID10 array (near layout) with four 8 GiB virtual hard drives, making a 16 GiB array (/dev/md0 formatted as ext4). On the other hand, I have a 16 GiB RAID1 array (/dev/md1, also formatted as ext4). The purpose of these setups is to compare the read and write performances of each... (13 Replies)
Discussion started by: gacanepa
13 Replies

7. Shell Programming and Scripting

Bash arrays: rebin/interpolate smaller array to large array

hello, i need a bit of help on how to do this effectively in bash without a lot of extra looping or massive switch/case i have a long array of M elements and a short array of N elements, so M > N always. M is not a multiple of N. for case 1, I want to stretch N to fit M arrayHuge H = (... (2 Replies)
Discussion started by: f77hack
2 Replies

8. UNIX for Beginners Questions & Answers

Bash array variables are changed in loop runtime

I am trying to check whether particular host and port are responding or not. I am using below script to check. but node_port array that i am using in loop is getting replaced with previous iteration value. Script and output is given. Please help me to understanding why node_port values are... (5 Replies)
Discussion started by: tmalik79
5 Replies

9. Shell Programming and Scripting

Bash Array connectin to another Array

Hello, i have a script that i need account_number to match a name. for exsample : ACCOUNT_ID=(IatHG8DC7mZbdymSoOr11w KbnlG2j-KRQ0-1_Xk356s8) and i run a loop curl requst with this the issue is that i want to know on which account were talking about so bash will know this : ... (4 Replies)
Discussion started by: batchenr
4 Replies

10. Shell Programming and Scripting

Bash for loop array

Hi there, A bit new to bash and am having an issue with a for loop. I look for filenames in a specified directory and pull the date string from each meeting a certain criteria, and then would like to make a directory for each date found, like this: search 20180101.gz 20180102.gz 20180103.gz... (5 Replies)
Discussion started by: mwheeler12
5 Replies
RBASH(1)						      General Commands Manual							  RBASH(1)

NAME
rbash - restricted bash, see bash(1) RESTRICTED SHELL
If bash is started with the name rbash, or the -r option is supplied at invocation, the shell becomes restricted. A restricted shell is used to set up an environment more controlled than the standard shell. It behaves identically to bash with the exception that the follow- ing are disallowed or not performed: o changing directories with cd o setting or unsetting the values of SHELL, PATH, ENV, or BASH_ENV o specifying command names containing / o specifying a filename containing a / as an argument to the . builtin command o specifying a filename containing a slash as an argument to the -p option to the hash builtin command o importing function definitions from the shell environment at startup o parsing the value of SHELLOPTS from the shell environment at startup o redirecting output using the >, >|, <>, >&, &>, and >> redirection operators o using the exec builtin command to replace the shell with another command o adding or deleting builtin commands with the -f and -d options to the enable builtin command o using the enable builtin command to enable disabled shell builtins o specifying the -p option to the command builtin command o turning off restricted mode with set +r or set +o restricted. These restrictions are enforced after any startup files are read. When a command that is found to be a shell script is executed, rbash turns off any restrictions in the shell spawned to execute the script. SEE ALSO
bash(1) GNU Bash-4.0 2004 Apr 20 RBASH(1)
All times are GMT -4. The time now is 07:53 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy