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Top Forums Shell Programming and Scripting Read random line from a text file Post 302356052 by Bashar on Thursday 24th of September 2009 06:43:01 PM
Old 09-24-2009
hehe not classroom check my IP i'm working at office Smilie

---------- Post updated 09-25-09 at 01:43 AM ---------- Previous update was 09-24-09 at 06:17 PM ----------

google answered me, i don't know why people start not to help each others anymore on forums, it seems forums gonna eventually die like IRC channels when it was so popular in 90s Smilie

Code:
#!/bin/sh

LINES=`wc -l $1 | awk '{ print ($1 + 1) }'`
RANDSEED=`date '+%S%M%I'`
LINE=`cat $1 | awk -v COUNT=$LINES -v SEED=$RANDSEED 'BEGIN { srand(SEED); \
i=int(rand()*COUNT) } FNR==i { print $0 }'`
echo $LINE

save it into rand.sh for example then chmod + rand.sh and then ./rand.sh text_file_goes_here and it will do the magic



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rand(3C)																  rand(3C)

NAME
rand(), rand_r(), srand() - simple random-number generator SYNOPSIS
DESCRIPTION
uses a multiplicative, congruential, random-number generator with period 2^32 that returns successive pseudo-random numbers in the range from 0 to 2^15-1. can be called at any time to reset the random-number generator to a random starting point. The generator is initially seeded with a value of 1. returns a random number at the address pointed to by the randval parameter. The seed parameter can be set at any time to start the random- number generator at an arbitrary point. Note The spectral properties of leave a great deal to be desired. provides a much better, though more elaborate, random-number generator (see drand48(3C)). RETURN VALUE
If seed or randval is NULL, returns 0. Otherwise, returns a psuedo-random integer. EXAMPLES
The following: int x, y; srand(10); x = rand(); y = rand(); would produce the same results as: int x, y, s = 10; x=rand_r(&s); y=rand_r(&s); WARNINGS
Users of should note that rand_r() now conforms with POSIX.1c. The old prototype of is supported for compatibility with existing DCE applications only. SEE ALSO
drand48(3C), random(3M), thread_safety(5), random(7). STANDARDS CONFORMANCE
rand(3C)
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