what I do wrong

[pepi37]

results.txt
---------------------------------------------------------------------------
[Sat Jul 11 23:04:00 2015]
2*11^13355+1 is not prime. RES64: 2BC6AF8D47953C43. We8: 68566856,00000000
2*11^13356+1 is not prime. RES64: 27FF3175F85CE71C. We8: 68586858,00000000
2*11^13357+1 is not prime. RES64: 0FE8C886B553D211. We8: 685A685A,00000000
2*11^13359+1 is a probable prime! We8: 685E685E,00000000
---------------------------------------------------------------------------

clear
echo
echo " **** UP TIME **** "
echo " "

to see does computer work all time

uptime | sed 's/^.* up \+\(.\+\), \+[0-9] user.*$/\1/'
echo " "
echo " **** PRP FOUND **** "
echo " "

check is anywhere "prime!" and display it

grep -h 'prime!' /pepi/mprime/results.txt | cut -d"W" -f1
grep -h 'prime!' /pepi/res.txt | cut -d"W" -f1
grep -h 'prime!' /pepi/prp.txt | cut -d"W" -f1
echo " "
echo "COLLECTING RESULTS"
cat /pepi/mprime/results.txt >> res.txt
for fname in /pepi/mprime/results.txt

collect results to file res.txt and delete results.txt

do
> $fname
done
echo "COLLECTING DONE "
echo " "
grep -h 'prime.' /pepi/res.txt | cut -d"W" -f1 > res.txt

remove part of line I dont need

wc -l < /pepi/res.txt

count lines in res.txt and display result

grep "!" /pepi/res.txt >> prp.txt

copy line with "!" to file prp.txt

echo " "
echo NUMBER of PRIMES
wc -l prp.txt | cut -d "p" -f1

counts number of lines in prp.txt and display result

sleep 2
exit


What I do wrong?
This is my script that collects results from file, remove part of lines, and wrote that in res.txt and prp.txt
And all is ok if there is data in "initial file"- results.txt, this script do exactly what I wont
But if results.txt is empty, then script also delete content of res.txt?
Why, where is error?
Thanks for any advice!

[Mark Rose]

grep -h 'prime.' /pepi/res.txt | cut -d"W" -f1 > res.txt

The single > will always overwrite the file.

You could test if the file is empty at the beginning and exit or whatever:

if [[ ! -s /pepi/res.txt ]] ; then exit ; fi

[Dubslow]

Or use ">>" (appends without overwriting)

[pepi37]

Originally Posted by Dubslow

Or use ">>" (appends without overwriting)

If I do that then number of lines id doubled in every checking, so that is not solution.
But I dont know why is doubling if initial file is empty.

if [[ ! -s /pepi/res.txt ]] ; then exit ; fiT

his throw some error, so it doesnot work :(

[pepi37]

I found where error was.
I must create temporary file and then delete it

grep -h 'prime.' /pepi/resu.txt | cut -d"W" -f1 >> results.txt
rm resu.txt

Now all is perfect!
Thanks for help!