diff --git a/src/lib/backup.sh b/src/lib/backup.sh
index ecea702..3bba2e9 100644
--- a/src/lib/backup.sh
+++ b/src/lib/backup.sh
@@ -33,10 +33,10 @@ process_source() {
     echo -e "Processing source $uri ..."
 
     case "$scheme" in
-        file)   handler='backup_files';;
-        mysql)  handler='backup_mysql';;
-        postgres) handler='backup_postgres';;
-        sqlite) handler='backup_sqlite';;
+        file)   handler='handler::tar';;
+        mysql)  handler='handler::mysqldump';;
+        postgres) handler='handler::pg_dump';;
+        sqlite) handler='handler::sqlite';;
         *) echo "Error: $__user_script: Unsupported URI scheme: $scheme" >&2; exit 1;;
     esac
 
@@ -62,15 +62,15 @@ process_target() {
     echo -e "Processing target $uri ..."
 
     case "$scheme" in
-        file)   handler='transfer_files';;
-        ftp)    handler='transfer_ftp';;
-        sftp)   handler='transfer_sftp';;
-        rsync)  handler='transfer_rsync';;
-        s3)     handler='transfer_s3';;
-        sj)     handler='transfer_sj';;
-        swift)  handler='transfer_swift';;
-        dav)    handler='transfer_dav';;
-        davs)   handler='transfer_davs';;
+        file)   handler='handler::cp';;
+        ftp)    handler='handler::ftp';;
+        sftp)   handler='handler::sftp';;
+        rsync)  handler='handler::rsync';;
+        s3)     handler='handler::s3';;
+        sj)     handler='handler::sj';;
+        swift)  handler='handler::swift';;
+        dav)    handler='handler::dav';;
+        davs)   handler='handler::davs';;
         *) echo "Error: Unsupported URI scheme: $scheme" >&2; exit 1;;
     esac
 
@@ -93,211 +93,10 @@ builtin_backup() {
     done
 }
 
-# ---------------------------------------------------------- #
-# * Backup functions                                         #
-# ---------------------------------------------------------- #
-
-backup_files() {
-    # Backup local files with tar(1). Handle 'file' URI scheme.
-    #
-    # Usage: backup_files URI
-
-    local uri
-    local src_path
-    local dst_path
-    local opts
-    local archive
-    local compr
-    local exclude
-    local file_ext
-
-    uri="$1"
-    dst_path="$__main_target_path"
-
-    parse_uri "$uri"
-
-    if [ -f "$path" ] || [ -d "$path" ]; then
-        src_path="$path"
-    else
-        echo "Error: Path '$path' from URI '$uri' does not exists" >&2
-        exit 1
-    fi
-
-    if [[ "$src_path" == "$dst_path" ]]; then
-        echo "Error: Source and destination paths is the same: $src_path; $dst_path" >&2
-        exit 1
-    fi
-
-    # Exit if tar is not installed
-    is_installed tar
-
-    # Overwrire __tar_options
-    if [ -n "$tar_options" ]; then
-        opts="$tar_options"
-    else
-        opts="$__tar_options"
-    fi
-
-    # Overwrite __tar_exclude
-    if [ "$tar_exclude" ]; then
-        for item in "${tar_exclude[@]}"; do
-            exclude+=" --exclude $item"
-        done
-    else
-        exclude=
-    fi
-
-    # Overwrite __compression
-    if [ "$compression" ]; then
-        compr="$compression"
-    else
-        compr="$__compression"
-    fi
-
-    # Select filename extension by compression type.
-    # Make sure for the `--auto-compress` is enabled in __tar_options
-    # Refference: https://www.gnu.org/software/tar/manual/html_node/gzip.html
-    case "$compr" in
-        gzip|gz)    file_ext='.tar.gz';;    # gzip
-        tgz)        file_ext='.tgz';;       # gzip
-        taz)        file_ext='.taz';;       # gzip
-        compress|Z) file_ext='.tar.Z';;     # compress
-        taZ)        file_ext='.taZ';;       # compress
-        bzip2|bz2)  file_ext='.tar.bz2';;   # bzip2
-        tz2)        file_ext='.tz2';;       # bzip2
-        tbz2)       file_ext='.tbz2';;      # bzip2
-        tbz)        file_ext='.tbz';;       # bzip2
-        lzip|lz)    file_ext='.tar.lz';;    # lzip
-        lzma)       file_ext='.tar.lzma';;  # lzma
-        tlz)        file_ext='.tlz';;       # lzma
-        lzop|lzo)   file_ext='.tar.lzo';;   # lzop
-        xz)         file_ext='.tar.xz';;    # xz
-        zstd|zst)   file_ext='.tar.zst';;   # zstd
-        tzst)       file_ext='.tzst';;      # zstd
-        *)          file_ext='.tar.gz';;    # Force gzip
-    esac
-
-    archive="${dst_path}/$(gen_backup_name "$file_ext")"
-
-    [ "$__verbose" ] && {
-        echo "Source path: $src_path"
-        echo "Destination path: $dst_path"
-        echo "Command: tar $exclude $opts $archive $src_path"
-    }
-
-    log "Archiving $src_path to $archive ..."
-    log "Command: tar $exclude $opts $archive $src_path"
-
-    # Run tar
-    try tar "$exclude" "$opts" "$archive" "$src_path"
-
-    # Append path to 'backups' array
-    backups+=("$archive")
-}
-
-backup_mysql() {
-    echo Not implemented >&2; exit 1
-}
-
-backup_postgres() {
-    echo Not implemented >&2; exit 1
-}
-
-backup_sqlite() {
-    echo Not implemented >&2; exit 1
-}
-
-# ---------------------------------------------------------- #
-# * Functions for targets processing                         #
-# ---------------------------------------------------------- #
-
-transfer_files() {
-    # Transfer files to another location from __main_target_path using cp(1)
-    #
-    # Usage: transfer_files URI
-
-    local uri
-    local dst_path
-
-    uri="$1"
-
-    if [[ "$uri" == "$__main_target" ]]; then
-        : # Do nothing. Source and destination is the same
-    else
-        # Copy backups to another destination
-        parse_uri "$uri"
-
-        if [ -f "$path" ] || [ -d "$path" ]; then
-            dst_path="$path"
-        else
-            echo "Error: Path '$path' from URI '$uri' does not exists" >&2
-            exit 1
-        fi
-
-        [ "$__verbose" ] && echo "Destination path: $dst_path"
-
-        # Copy files preserving metadata
-        for backup in "${backups[@]}"; do
-            log "Copying file $backup to $dst_path ..."
-            [ "$__verbose" ] && echo "Command: cp --archive $backup $dst_path"
-            try cp --archive "$backup" "$dst_path"
-        done
-    fi
-}
-
-transfer_ftp() {
-    echo Not implemented >&2; exit 1
-}
-
-transfer_sftp() {
-    echo Not implemented >&2; exit 1
-}
-
-transfer_rsync() {
-    echo Not implemented >&2; exit 1
-}
-
-transfer_s3() {
-    echo Not implemented >&2; exit 1
-}
-
-transfer_sj() {
-    echo Not implemented >&2; exit 1
-}
-
-transfer_swift() {
-    echo Not implemented >&2; exit 1
-}
-
-transfer_dav() {
-    echo Not implemented >&2; exit 1
-}
-
-transfer_davs() {
-    echo Not implemented >&2; exit 1
-}
-
 # ---------------------------------------------------------- #
 # * Helper functions                                         #
 # ---------------------------------------------------------- #
 
-is_installed() {
-    # Check if the program is installed.
-    # See good answer: https://stackoverflow.com/a/677212
-    #
-    # Usage: is_installed COMMAND
-
-    local cmd
-
-    cmd="$1"
-
-    if ! command -v "$cmd" >/dev/null 2>&1; then
-        echo "Error: Command $cmd not found." \
-            "Please install $cmd or check your PATH if it's actually installed." >&2
-        exit 1
-    fi
-}
-
 gen_backup_name() {
     # Generate backup file name. Return (echo) string.
     #
diff --git a/src/lib/handlers/cp.sh b/src/lib/handlers/cp.sh
new file mode 100644
index 0000000..c3a9c87
--- /dev/null
+++ b/src/lib/handlers/cp.sh
@@ -0,0 +1,52 @@
+#!/usr/bin/env bash
+
+# cp.sh - copy files to new location.
+# Copyright (c) 2022 ge <https://nixhacks.net/>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+handler::cp() {
+    # Transfer files to another location from __main_target_path using cp(1)
+    # Handle 'file' URI scheme.
+    #
+    # Usage: handler::cp URI
+
+    local uri
+    local dst_path
+
+    uri="$1"
+
+    if [[ "$uri" == "$__main_target" ]]; then
+        : # Do nothing. Source and destination is the same
+    else
+        # Copy backups to another destination
+        parse_uri "$uri"
+
+        if [ -f "$path" ] || [ -d "$path" ]; then
+            dst_path="$path"
+        else
+            echo "Error: Path '$path' from URI '$uri' does not exists" >&2
+            exit 1
+        fi
+
+        [ "$__verbose" ] && echo "Destination path: $dst_path"
+
+        # Copy files preserving metadata
+        for backup in "${backups[@]}"; do
+            log "Copying file $backup to $dst_path ..."
+            [ "$__verbose" ] && echo "Command: cp --archive $backup $dst_path"
+            try cp --archive "$backup" "$dst_path"
+        done
+    fi
+}
diff --git a/src/lib/handlers/tar.sh b/src/lib/handlers/tar.sh
new file mode 100644
index 0000000..880a417
--- /dev/null
+++ b/src/lib/handlers/tar.sh
@@ -0,0 +1,115 @@
+#!/usr/bin/env bash
+
+# tar.sh - backup files via tar.
+# Copyright (c) 2022 ge <https://nixhacks.net/>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+handler::tar() {
+    # Backup local files with tar(1). Handle 'file' URI scheme.
+    #
+    # Usage: handler::tar URI
+
+    local uri
+    local src_path
+    local dst_path
+    local opts
+    local archive
+    local compr
+    local exclude
+    local file_ext
+
+    uri="$1"
+    dst_path="$__main_target_path"
+
+    parse_uri "$uri"
+
+    if [ -f "$path" ] || [ -d "$path" ]; then
+        src_path="$path"
+    else
+        echo "Error: Path '$path' from URI '$uri' does not exists" >&2
+        exit 1
+    fi
+
+    if [[ "$src_path" == "$dst_path" ]]; then
+        echo "Error: Source and destination paths is the same: $src_path; $dst_path" >&2
+        exit 1
+    fi
+
+    # Exit if tar is not installed
+    is_installed tar
+
+    # Overwrire __tar_options
+    if [ -n "$tar_options" ]; then
+        opts="$tar_options"
+    else
+        opts="$__tar_options"
+    fi
+
+    # Overwrite __tar_exclude
+    if [ "$tar_exclude" ]; then
+        for item in "${tar_exclude[@]}"; do
+            exclude+=" --exclude $item"
+        done
+    else
+        exclude=
+    fi
+
+    # Overwrite __compression
+    if [ "$compression" ]; then
+        compr="$compression"
+    else
+        compr="$__compression"
+    fi
+
+    # Select filename extension by compression type.
+    # Make sure for the `--auto-compress` is enabled in __tar_options
+    # Refference: https://www.gnu.org/software/tar/manual/html_node/gzip.html
+    case "$compr" in
+        gzip|gz)    file_ext='.tar.gz';;    # gzip
+        tgz)        file_ext='.tgz';;       # gzip
+        taz)        file_ext='.taz';;       # gzip
+        compress|Z) file_ext='.tar.Z';;     # compress
+        taZ)        file_ext='.taZ';;       # compress
+        bzip2|bz2)  file_ext='.tar.bz2';;   # bzip2
+        tz2)        file_ext='.tz2';;       # bzip2
+        tbz2)       file_ext='.tbz2';;      # bzip2
+        tbz)        file_ext='.tbz';;       # bzip2
+        lzip|lz)    file_ext='.tar.lz';;    # lzip
+        lzma)       file_ext='.tar.lzma';;  # lzma
+        tlz)        file_ext='.tlz';;       # lzma
+        lzop|lzo)   file_ext='.tar.lzo';;   # lzop
+        xz)         file_ext='.tar.xz';;    # xz
+        zstd|zst)   file_ext='.tar.zst';;   # zstd
+        tzst)       file_ext='.tzst';;      # zstd
+        *)          file_ext='.tar.gz';;    # Force gzip
+    esac
+
+    archive="${dst_path}/$(gen_backup_name "$file_ext")"
+
+    [ "$__verbose" ] && {
+        echo "Source path: $src_path"
+        echo "Destination path: $dst_path"
+        echo "Command: tar $exclude $opts $archive $src_path"
+    }
+
+    log "Archiving $src_path to $archive ..."
+    log "Command: tar $exclude $opts $archive $src_path"
+
+    # Run tar
+    try tar "$exclude" "$opts" "$archive" "$src_path"
+
+    # Append path to 'backups' array
+    backups+=("$archive")
+}