Image to pdf

#!/bin/bash
 #tiff-to-pdf is 6 to 7 times faster script than this script
 start_time=`date +%s`
 ########## Section 1 ##########
 # This command can convert any image to PDF document, version 1.3 ( very slow as compared to tiff2pdf ) but slightly faster than section 2

mogrify -format pdf *

######### Section 2 ##########
 # this command can convert any image to PDF document, version 1.3

#ls  | while read filename; do
 #file=`echo $filename |sed 's/\(.*\)\..*/\1/'`
 #convert $filename $file.pdf
 #done

finish_time=`date +%s`

echo "Time duration: `expr $finish_time - $start_time` secs."

Check up/down hosts in your network

To check how many systems are up and how many systems are down in network.use below script

I used nohup to avoid ping output on screen

for i in {1..254} ; do ip=192.168.0.$i && nohup ping -c1 $ip 2> /dev/null && echo "$ip online" || echo "$ip offline" ; done