file server

client.sh

#!/bin/bash
echo "$$ Started process">&2;
if [[ $1 != "RUNSERVER" ]] ; then
    echo "Started client mode" >&2;
    [ ! $2 -ge 1025 ] && [ ! $2 -ge 1025 ] && echo "Invalid port number, must be 1025 to 65535" && exit 1;
    [[ ! $1 =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]] && echo "Invalid ip format" && exit 1;
    socat  TCP4:$1:$2  EXEC:"$0 RUNSERVER $$";
    if [ ! $? -eq 0 ] ; then
        echo "could not connect check host/ip and port and server"
    fi
    exit 1;
fi

echo "$$ Started connection">&2;
while true ; do
echo "$$ Pick LIST GET PUT" > /proc/$2/fd/1;
read i  </proc/$2/fd/0;
echo "$$ Read $i case" >&2;
case ${i^^} in
    LIST )
        echo "LIST"
        read redi ;
        echo -e "$redi" | tr  "\t" "\n" >&2;
        ;;
    GET )
        echo "GET"
        echo "$$ Insert filename" >&2;
        read string  </proc/$2/fd/0;
        echo "$string";
        echo "$$ Learned name is $string" >&2;
        read  size ;
        echo "$$ Learned size is $size bytes" >&2;
        [ $size -ge 0 ] && head -c $size <&0 >${string##*/};
        [ ! $size -ge 0 ] && echo "$$ Invalid file" >&2;;
    PUT )
        echo "PUT"
        read string  </proc/$2/fd/0;
        echo "$string ";
        if [ -f $string ]; then
        stat "$string"  --format "%s" ;
        echo "$$ Sent size is $(stat "$string"  --format "%s")" >&2;
        cat <"$string";
        else
        echo "$$ File does not exist" >&2;
        echo "-1";
        fi;;
    *)
        echo "$$ Invalid"  >&2;
        break;;
esac
done
echo "$$ Ending connection">&2;

server.sh

#!/bin/bash
if [[ $1 != "RUNSERVER" ]] ; then
    echo "Started server mode" >&2;
    [ ! $1 -ge 1025 ] && [ ! $1 -ge 1025 ] && echo "Invalid port number, must be 1025 to 65535" && exit 1;
    [ ! -d $2 ]  && echo "Directory $2 DOES NOT exists." && exit 1;
    ScriptPath=$PWD
    cd $2;
    socat TCP4-LISTEN:$1,reuseaddr,fork EXEC:"$ScriptPath/$0 RUNSERVER";
    exit 1;
fi
echo "$$ Started connection">&2;
while true ; do
read  i ;
echo "$$ Read $i case" >&2;
case $i in
    LIST)
        ls -a | tr "\n" "\t" ;
        echo "";
        ;;
    GET)
        read string ;
        echo "$$ Read name is $string" >&2;
        if [ -f $string ]; then
        stat "$string"  --format "%s" ;
        echo "$(stat "$string"  --format "%s") is file size sent" >&2;
        cat <"$string";
        else
        echo "$$ File does not exist" >&2;
        echo -1;
        fi;;
    PUT)
        read  name ;
        echo "$$ Got name $name" >&2;
        read  size ;
        echo "$$ Learned size is $size bytes" >&2;
        [ $size -ge 0 ] && head -c $size <&0 >${name##*/};
        [ $size -ge 0 ] && echo "$$ Recieve ended"  >&2;
        [ ! $size -ge 0 ] && echo "$$ File does not exist" >&2;;
    *)
        echo "$$ Invalid"  >&2;
        break;;
esac
done
echo "$$ Ending connection">&2;