diff --git a/Dockerfile b/Dockerfile
index becaa45..2b131c2 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,8 +1,8 @@
 FROM alpine:latest
 
-RUN apk --no-cache add openssh-client jq \
+RUN apk --no-cache add bash openssh-client jq \
  && adduser --no-create-home --uid 1000 -D user \
  && mkdir -p /opt/resource/
 USER 1000:1000
-WORKDIR /tmp/
-COPY check in out /opt/resource/
+WORKDIR /opt/resource/
+COPY common check in out /opt/resource/
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..57a1150
--- /dev/null
+++ b/README.md
@@ -0,0 +1,17 @@
+# concourse-ssh-resource
+
+A resource type for a ssh resource
+
+## Source configuration
+
+```
+
+
+```
+
+- hostname: *Required*. Servers hostname to connect to.
+- port: *Optional*. *Default* `22`. Port the ssh server accepts connections on.
+- user: *Required*. User as which to connect.
+- identity: *Required*. The private key used to authenticate.
+- hostkey: *Required*. The hostkey of the server.
+- files: *Optional*. File paths on the remote to get/put
diff --git a/check b/check
index 0617957..6369a3e 100755
--- a/check
+++ b/check
@@ -1 +1,53 @@
 #!/usr/bin/env sh
+
+set -e
+
+. ./common
+
+fetch_file_infos() {
+    files_file="$(mktemp -tp /tmp)"
+ssh -F "$CONFIG_PATH" "$HOSTNAME" sh -s << EOF > "$files_file"
+    files="$(get_files)"
+    echo "\$files" | while read -r file; do
+        echo "\$file"
+        [ -e "\$file" ] && echo true || echo false
+        [ -e "\$file" ] && echo "\$(stat --format=%Y "\$file")" || echo
+    done
+EOF
+    echo "$files_file"
+    return 0
+}
+
+_compute_version() {
+    echo "["
+    last_line=
+    line_file=
+    line_exists=
+    line_modify=
+    while read -r line; do
+        if [ -z "$line_file" ]; then
+            line_file="$line"
+        elif [ -z "$line_exists" ]; then
+            line_exists="$line"
+        elif [ -z "$line_modify" ]; then
+            line_modify="$line"
+        else
+            if "$line_exists"; then
+                echo '{"path":' "\"$line_file\"," '"modify":' "$line_modify" '}',
+            fi
+            line_file="$line"
+            line_exists=
+            line_modify=
+        fi
+    done < "$1"
+    if [ -n "$line_file" ] && [ -n "$line_exists" ] && [ -n "$line_modify" ] && "$line_exists"; then
+        echo '{"path":' "\"$line_file\"," '"modify":' "$line_modify" '}'
+    fi
+    echo "]"
+}
+
+compute_version() {
+    _compute_version "$@" | jq -r tostring
+}
+
+compute_version "$(fetch_file_infos)"
diff --git a/common b/common
new file mode 100755
index 0000000..0894a77
--- /dev/null
+++ b/common
@@ -0,0 +1,61 @@
+#!/usr/bin/env sh
+
+INPUT_PATH=
+CONFIG_PATH=
+HOSTNAME=
+PORT=
+USER=
+IDENTITY=
+HOSTKEY=
+
+save_input() {
+    input_file="$(mktemp -tp /tmp)"
+    cat > "$input_file" <&0
+    echo "$input_file"
+    return 0
+}
+
+read_config() {
+    HOSTNAME="$(jq -r .source.hostname < "$1")"
+    PORT="$(jq -r '.source.port // "22"' < "$1")"
+    USER="$(jq -r .source.user < "$1")"
+    IDENTITY="$(jq -r .source.identity < "$1")"
+    HOSTKEY="$(jq -r .source.hostkey < "$1")"
+    return 0
+}
+
+write_config() {
+    directory="$(mktemp -dp /tmp)"
+    config="$directory/config"
+    identity_file="$directory/identity"
+    knownhosts_file="$directory/knownhosts"
+
+    {
+        echo "host $HOSTNAME"
+        echo "    HostName $HOSTNAME"
+        echo "    Port $PORT"
+        echo "    User $USER"
+        echo "    IdentityFile $identity_file"
+        echo "    UserKnownHostsFile $knownhosts_file"
+    } > "$config"
+    echo "$IDENTITY" > "$identity_file"
+    echo "$HOSTKEY" > "$knownhosts_file"
+    chmod 600 "$identity_file" "$knownhosts_file" "$config"
+    echo "$config"
+    return 0
+}
+
+INPUT_PATH="$(save_input)"
+read_config "$INPUT_PATH"
+CONFIG_PATH="$(write_config)"
+
+export INPUT_PATH
+export CONFIG_PATH
+
+get_version() {
+    jq -r '.version // []' < "$INPUT_PATH"
+}
+
+get_files() {
+    jq -r '.source.files?[]' < "$INPUT_PATH"
+}
diff --git a/in b/in
index 0617957..6842d56 100755
--- a/in
+++ b/in
@@ -1 +1,39 @@
-#!/usr/bin/env sh
+#!/usr/bin/env bash
+
+set -e
+set -o pipefail
+
+. ./common
+
+cd "$1"
+ssh -F "$CONFIG_PATH" "$HOSTNAME" sh -s << EOF | tar x
+    files="$(get_version | jq -r .[].path)"
+    archive="\$(mktemp -t)"
+    files_path="\$(mktemp -t)"
+    head --bytes=10240 /dev/zero > "\$archive"
+    echo "\$files" > "\$files_path"
+    error=false
+    while read -r filepath; do
+        if [ ! -e "\$filepath" ]; then
+            echo "File not found on remote: \$filepath" >&2
+            error=true
+            break
+        fi
+        tar rf "\$archive" "\$filepath"
+    done < "\$files_path"
+    if ! "\$error"; then
+        cat "\$archive"
+    fi
+    rm "\$archive"
+    if "\$error"; then
+        exit 1
+    else:
+        exit 0
+    fi
+EOF
+
+jq -r tostring << EOF
+{
+    "version": $(get_version)
+}
+EOF