Shell Programming and Scripting

for i in {1..n}; do ./script.sh & done

#!/usr/bin/ksh
 
 
lock_wait(){
 
path="/home/yadis/tests"
rmds=$((RANDOM%10))
 
    while true; do
       if mkdir "${path}.lock.d"; then
         break;
         fi
      sleep $rmds
   done
}
 
remove_lock(){
path="/home/yadis/tests"
rmdir "${path}.lock.d"
}
 
leer(){
 
   fecha=`date +%d`"/"`date +%m`"/"`date +%Y`"_"`date +%H`:`date +%M`:`date +%S`
lock_wait
 
   num=`cat file.txt`
   print $num "file.txt" $fecha 
   print $num "file.txt" $fecha >> filelog
 
num=$(($num+1))
print $num > file.txt
remove_lock
 
if [[ num -ge 100 ]]; then
exit 1
else
 leer
fi
 
}
 
fecha=`date +%d`"/"`date +%m`"/"`date +%Y`"_"`date +%H`:`date +%M`:`date +%S`
 
print "script.sh" $fecha
 
leer

# pass file to lock as $1
function lock_it
{
    typeset lockname=$1.lock

    while ! mkdir $lockname 2>/dev/null    # if we can make it, we own the lock
    do
        echo "$$ waiting for lock"      # didn't get it, wait and try again
        sleep 3
   done

    touch $lockname/PID$$       # mark it with our pid (humans can easily tell which process owns the lock this way)
}

# pass file to unlock as $1
function unlock_it
{
    typeset lockname=$1.lock
    if [[ -d $lockname ]]      # ensure it exists
    then
        if [[ -f $lockname/PID$$ ]]    # ensure this process owns it
        then
            rm -fr $lockname
        else
            echo "unable to unlock $w: process $$ does not own the lock"
        fi
    else
        echo "unable to unlock $1: lock does not exist"
    fi
}


# simple test case
lock_it /tmp/test
echo "$$ got it"
sleep 30
echo "$$ releasing it"
unlock_it /tmp/test

while true; do
    mkdir "${path}.lock.d"
   if [[ -d "${path}.lock.d" ]]; then          
 break;         
 fi       
 sleep $rmds    
done

 while ! mkdir $lockname 2>/dev/null

ksh --version

#!/usr/bin/ksh
 
#!/usr/bin/ksh
max=$1
fecha=`date +%d`"/"`date +%m`"/"`date +%Y`"_"`date +%H`:`date +%M`:`date +%S`
print "process3.sh" $fecha
print "process3.sh" $fecha >>file.log
lock=0
until [[ $num -ge $max ]]; do
  fecha=`date +%d`"/"`date +%m`"/"`date +%Y`"_"`date +%H`:`date +%M`:`date +%S`
alea=$((RANDOM%3))
if test -f archivo.lock
then
    lock=1
    fi
    while [[ $lock -eq 1 ]] 
  do
    if test -f archivo.lock
    then
      lock=1
      print sleeping
      sleep $alea
    else
      lock=0
  fi
done
touch archivo.lock
  num=`cat archivo.txt`
  num=$(($num+1))
  print $num > archivo.txt
rm -f archivo.lock 
   print $num "archivo.txt" $fecha >>file.log
   print $num "archivo.txt" $fecha
done

for i in {1..n}; do script.sh & done

ps -ef | grep script

for x in `seq 1 5`
do
    shell-script >/tmp/log.$x 2>&1 &
done

lock_it()
{
    lockname=$1.lock

    while  true
    do
        if mkdir $lockname 2>/dev/null
        then
            touch $lockname/PID$$       # mark it with our pid
            return 0
        fi

        echo "$$ ($2) waiting for lock"
        sleep 3
   done

}

unlock_it()
{
    lockname=$1.lock
    if [ -d $lockname ]
    then
        if [ -f $lockname/PID$$ ]
        then
            rm -fr $lockname
            return 0
        else
            echo "$$ unable to unlock $w: process $$ does not own the lock"
        fi
    else
        echo "$$ unable to unlock $1: lock does not exist"
    fi

    return 1
}

if [ -z $1 ]
then
    for x in `seq 1 5`
    do
        echo "starting process $x"
        $0 $x &
    done

    ps -elf|grep "$0"
    wait
    exit
fi

lock_it /tmp/test $1
echo "$$ ($1) got the lock; sleeping 30s"
sleep 30
echo "$$ ($1) releasing lock"
unlock_it /tmp/test
echo "$$ ($1) is exiting"

exit

i=0
while [[ $i -lt $1 ]]; do
    ./script.sh $2 &
  i=$(($i+1))
   done

#!/usr/bin/ksh
max=$1
lock_it()
{
    lockname=dir.lock
while  true
    do
    if mkdir $lockname 2>/dev/null
    then
    touch $lockname/PID$$       # mark it with our pid
    return 0
    fi
    echo "$$ waiting for lock"
    sleep 3 
     done
}
unlock_it()
{
    lockname=dir.lock
     if [[ -d $lockname ]]
      then
    if [[ -f $lockname/PID$$ ]]
    then
   rm -fr $lockname
    return 0
    else
  echo "$$ unable to unlock $w: process $$ does not own the lock"
   fi
    else
    echo "$$ unable to unlock $1: lock does not exist"
   fi
 return 1
}

until [[ $num -ge $max ]]; do
  fecha=`date +%d`"/"`date +%m`"/"`date +%Y`"_"`date +%H`:`date +%M`:`date +%S`
alea=$((RANDOM%3))
lock_it
print "$$ got the lock" 
 print "$$ got the lock" >> file.log
 sleep $alea 
 print "$$ releasing the lock"
  num=`cat archivo.txt`
  num=$(($num+1))
  print $num > archivo.txt
  unlock_it 
  print "$$ exiting" 
  print $num "archivo.txt" $fecha  >>file.log
   print $num "archivo.txt $$" $fecha
done