#!/bin/bash
    pass='dpassspass'
    user='root@10.10.19.18'
    IP="10.2.1.41"
    path=/sys/variable/serv
    #not work## No such file or directory# write=$(sshpass -p $ovhpass ssh -t $user echo "$IP" > $path)
    sshpass -p $pass ssh -t $user  << EOF
    echo "$IP" > $path
    EOF
    my_var=$(sshpass -p $pass ssh -t $user "cd /sys_ovh; ./serv.bash")
    echo mystart-"$my_var"-myend
    read=$(sshpass -p $pass ssh -t $user cat $path)
    echo start-"$read"-end
    echo start-"$IP"-end
    if [ "$read" == "$IP" ]; then
    echo "run"
    fi

Connection to 10.10.19.18 closed.
-myendt-10.2.1.41
Connection to 10.10.19.18 closed.
-endt-10.2.1.41
start-10.2.1.41-end