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Full Discussion: Get 20% of lines in File randomly
Top Forums Shell Programming and Scripting Get 20% of lines in File randomly Post 302707225 by Lem on Friday 28th of September 2012 07:39:08 AM
Old 09-28-2012
If I'm right your problem is to randomly generate N integers in the range [1;M], where M is the number of lines in the file, and N is a rounded percentage of M.

Before going on: are repetitions allowed? In other words, may a number (a line in the file) be randomly selected more than once?

And: what are your shell and OS?

EDIT: solution proposed

However, this is a possible solution working on linux/bash, with repetitions not allowed:
Code:
#!/bin/bash
range=$(wc -l "$1" | cut -d " " -f1)
(( $range > 32768 )) && exit              ### max number of lines for this script: 32768
percent=$2                                ### set this  as you like, [1-100]
(( 0 < $2 )) && (( $2 < 101 )) || exit
lim=$(( $range * $percent / 100 ))
for ((i=0;i<lim;i++)); do
        num=$(( $RANDOM % $range + 1 ));
        arr[$i]=$num;
        for ((j=0;j<i;j++)); do
                (( ${arr[$j]} == $num )) && {
                        let i--
                        break; }
        done
done

for linenum in "${arr[@]}"; do
        line=$(sed -n "$linenum p" "$1")
        ### your stuff here, for example: ###
        echo "$linenum"$'\t'"### $line"
done

exit 0

Usage:
Code:
lem@biggy:/tmp$ ./file2 file2 30
6	### lim=$(( $range * $percent / 100 ))
19	###         ### your stuff here, for example: ###
11	###                 (( ${arr[$j]} == $num )) && {
10	###         for ((j=0;j<i;j++)); do
5	### (( 0 < $2 )) && (( $2 < 101 )) || exit
4	### percent=$2                                ### set this  as you like, [1-100]

--
Bye
Last edited by Lem; 09-28-2012 at 11:36 AM.. Reason: Solution proposed
This User Gave Thanks to Lem For This Post:
chercheur857
 

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LEARN ABOUT HPUX

xdevbell

XDeviceBell(3X11)						    X FUNCTIONS 						 XDeviceBell(3X11)

NAME

       XDeviceBell - ring a bell on a device supported through the input extension

SYNTAX

       Status XDeviceBell(display, device, feedbackclass, feedbackid, percent)
	     Display *display;
	     XDevice *device;
	     XID *feedbackclass;
	     XID *feedbackid;
	     int *percent;

ARGUMENTS

       display	   Specifies the connection to the X server.

       device	   Specifies the device with which the bell is associated.

       feedbackclass
		   Specifies the class of the feedback with which the bell is associated.

       feedbackid  Specifies the id of the feedback with which the bell is associated.

       percent	   Specifies the volume in the range -100 to 100 at which the bell should be rung.

DESCRIPTION

       The  XDeviceBell  request  causes  the server to ring a bell on the specified feedback of the specified device, if possible.  The specified
       volume is relative to the base volume for the bell.  If an invalid device is specified, a BadDevice error will be returned.  The  feedback-
       class  and  feedbackid  parameters  contain values returned by an XGetFeedbackControl request and uniquely identify the bell to ring.  If a
       feedbackclass is specified that does not support a bell, or if a nonexistent feedbackid is specified, or a percent value is specified  that
       is not in the range -100 to 100, a BadValue error will be returned.

       The volume at which the bell is rung when the percent argument is nonnegative is:

	      base - [(base * percent) / 100] + percent

       The volume at which the bell rings when the percent argument is negative is:

	      base + [(base * percent) / 100]

       To change the base volume of the bell, use XChangeFeedbackControl.

       XDeviceBell can generate a BadDevice or a BadValue error.

DIAGNOSTICS

       BadDevice   An  invalid device was specified.  The specified device does not exist, or has not been opened by this client via XOpenInputDe-
		   vice.

       BadValue    An invalid feedbackclass, feedbackid, or percent value was specified.

SEE ALSO

       XChangeFeedbackControl(3X), XBell(3X)
       Programming With Xlib

X Version 11							     Release 6							 XDeviceBell(3X11)
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