diff --git a/cli.bash b/cli.bash
new file mode 100644
index 0000000..9792ce9
--- /dev/null
+++ b/cli.bash
@@ -0,0 +1,139 @@
+#!/bin/usr/env bash
+
+import log
+
+declare -Ag cli__options=()
+declare -Ag cli__descriptions=()
+cli__program_name="$0"
+cli__order=()
+
+cli::reset() {
+    cli__order=()
+    declare -Ag cli__options=()
+    declare -Ag cli__descriptions=()
+}
+
+cli::set_program_name() {
+    local program_name="$1"
+
+    cli__program_name="${program_name}"
+}
+
+cli::_option_encode() {
+    local option="$1"
+
+    log::debug "Encoding ${option}"
+
+    echo "${option}"
+}
+
+cli::_option_decode() {
+    local option="$1"
+
+    log::debug "Decoding ${option}"
+
+    echo "${option}"
+}
+
+# if letter require argument, then subfix letter with ':'
+cli::add_option() {
+    local letter="$1"
+    local callback="$2"
+    local description="$3"
+
+    cli__order+=("$letter")
+    cli__options["${letter:0:1}"]="$callback"
+    cli__descriptions[$letter]="$description"
+}
+
+cli::print_help() {
+    local usage="Usage: ${cli__program_name}"
+    local description=""
+    local description_formatted=""
+    log::debug "${!cli__descriptions[@]}"
+    log::debug "values: ${cli__descriptions[*]}"
+    for letter in "${cli__order[@]}";do
+    description_formatted="${cli__descriptions["$letter"]//\\n/\\n                  }"
+        if [ "${letter:1:1}" = ":" ];then
+            usage+=" [-${letter:0:1} ...]"
+            description+="    -${letter:0:1} <...>      ${description_formatted}\n"
+        else
+            usage+=" [-${letter:0:1}]"
+            description+="    -${letter:0:1}            ${description_formatted}\n"
+        fi
+        if [ "$(echo -e "$usage" | tail -n1 | wc -m )" -gt 70 ];then
+            usage+="\n        "
+        fi
+    done
+    echo -e "${usage}\n\nOptions:\n${description}"
+}
+
+cli::handle() {
+    local all_options=""
+    for letter in "${cli__order[@]}";do
+        all_options+="${letter}"
+    done
+
+    while getopts ":${all_options}" opt; do
+        if [ "$opt" = ":" ];then
+            log::fatal "Option -${OPTARG} require an argument"
+        elif [ "$opt" = "?" ];then
+            log::fatal "Invalid option -${OPTARG}"
+        fi
+        ${cli__options[$opt]} "${OPTARG}"
+    done
+}
+
+cli_test__a=0
+cli_test__b=0
+cli_test__c=0
+
+cli_test::a_cb() {
+    cli_test__a=1
+}
+
+cli_test::b_cb() {
+    cli_test__b=$1
+}
+
+cli_test::c_cb() {
+    cli_test__c=1
+}
+
+cli_test::test_handle() {
+    cli::reset
+    cli::set_program_name "example"
+    cli::add_option "a" cli_test::a_cb "Example option a"
+    cli::add_option "b:" cli_test::b_cb "Example option b"
+    cli::add_option "c" cli_test::c_cb "Example option c"
+
+    cli::handle "-a" "-b" "sth"
+    unit::assert_eq "${cli_test__a}" "1"
+    unit::assert_eq "${cli_test__b}" "sth"
+    unit::assert_eq "${cli_test__c}" "0"
+}
+
+cli_test::test_help_gen() {
+    cli::reset
+    cli::set_program_name "example"
+    cli::add_option "a" cli_test::a_cb "Example option a"
+    cli::add_option "b:" cli_test::b_cb "Example option b"
+    cli::add_option "c" cli_test::c_cb "Example option c"
+
+    local expected_output
+    expected_output="Usage: example [-a] [-b ...] [-c]
+
+Options:
+    -a            Example option a
+    -b <...>      Example option b
+    -c            Example option c"
+    local output
+    output=$(cli::print_help)
+    
+    unit::assert_eq "${output}" "${expected_output}"
+}
+
+cli_test::all() {
+    unit::test cli_test::test_help_gen
+    unit::test cli_test::test_handle
+}
diff --git a/exec.bash b/exec.bash
index 82c5e3b..c117f28 100644
--- a/exec.bash
+++ b/exec.bash
@@ -20,16 +20,44 @@ exec::silent() {
     fi
 }
 
+exec::retried_exec() {
+    local retries=$1
+    local sleep=$2
+    shift;shift
+    local try
+    local log
+    for ((try=0; try<retries; try++)) {
+        if log="$("$@" 2>&1)" &>/dev/null;then
+            return 0
+        fi
+        if [ "$DEBUG" = "1" ];then
+            echo "$log" >&2
+        fi
+        sleep "$sleep"
+    }
+    log::error "Command $* failed $retries times"
+    log::error "$log"
+    return 1
+}
+
 exec__sudo_keeping=0
 
 exec::sudo_keep_alive() {
+    exec::assert_cmd "sudo"
     if [ "$exec__sudo_keeping" != "1" ];then
         exec__sudo_keeping=1
-        sudo -v
+        if ! sudo -v;then
+            log::fatal "sudo authentication failed"
+        fi
         while true; do sudo -n true; sleep 60; kill -0 "$$" || exit; done 2>/dev/null &
     fi
 }
 
+exec::sudo() {
+    exec::sudo_keep_alive
+    sudo "$@"
+}
+
 exec::is_cmd_available() {
     local cmd="$1"
     if command -v "$cmd" &>/dev/null;then
@@ -49,7 +77,7 @@ exec::is_fn() {
 exec::assert_cmd() {
     local cmd="$1"
     if ! exec::is_cmd_available "$cmd";then
-        log::panic "Command \`$cmd\` is not available, but is required by this application"
+        log::fatal "Command \`$cmd\` is not available, but is required by this application"
     fi
 }
 
diff --git a/fetch.bash b/fetch.bash
index abeb65c..9687a4b 100644
--- a/fetch.bash
+++ b/fetch.bash
@@ -23,6 +23,15 @@ fetch::download_stream() {
     curl -sfL "$url"
 }
 
+fetch::file_exists() {
+    local url=$1
+    if curl --output /dev/null --silent --head --fail -L "$url";then
+        return 0
+    else
+        return 1
+    fi
+}
+
 fetch::verify() {
     local sha=$1
     local file=$2
diff --git a/github.bash b/github.bash
index b6a77a9..a9f43cd 100644
--- a/github.bash
+++ b/github.bash
@@ -5,7 +5,7 @@ github::latest_release() {
     local _repo=$1
     local -n output_version=$2
     local _url
-    _url=$(curl -w "%{url_effective}" -I -L -s -S "https://github.com/$_repo/releases/latest" -o /dev/null)
+    _url=$(curl -f -w "%{url_effective}" -I -L -s -S "https://github.com/$_repo/releases/latest" -o /dev/null)
     if [ "$_url" != "https://github.com/$_repo/releases" ];then
         # shellcheck disable=SC2034
         output_version=$(echo -n "$_url"| sed -e 's|.*/||')
@@ -33,7 +33,7 @@ github::latest_commit() {
     local -n output_sha=$3
     exec::assert_cmd jq
     local _json
-    _json=$(curl -s -L "https://api.github.com/repos/$_repo/commits/$_branch")
+    _json=$(curl -f -s -L "https://api.github.com/repos/$_repo/commits/$_branch")
     local _sha=""
     if _sha=$(echo -n "$_json" | jq '.sha' -re);then
         # shellcheck disable=SC2034
diff --git a/installer.bash b/installer.bash
index 5568ce5..6f72633 100644
--- a/installer.bash
+++ b/installer.bash
@@ -85,7 +85,7 @@ installer::copy_file() {
     if [ -f "$dst" ];then
         local backup=""
         tmp::create_persistent_file backup "backup" "$installer__files_dir"
-        cp "$dst" "$backup"
+        cp -p "$dst" "$backup"
         local relative_backup="${backup##$installer__dir/}"
         installer::_add_sha_item "$installer__dir" "$relative_backup"
         installer::_write_line "log 'Restoring $dst'"
diff --git a/log.bash b/log.bash
index dbed36f..78cecf9 100644
--- a/log.bash
+++ b/log.bash
@@ -1,6 +1,15 @@
 #!/usr/bib/env bash
 
 log__debug=0
+log__colors=-1
+
+log::detect_colors() {
+    if [ -t 1 ];then
+        log__colors=1
+    else
+        log__colors=0
+    fi
+}
 
 log::enable_debug() {
     log__debug=1
@@ -10,10 +19,27 @@ log::disable_debug() {
     log__debug=0
 }
 
+log::disable_colors() {
+    log__colors=0
+    log::debug "Colors forcefuly disabled"
+}
+
+log::enable_colors() {
+    log__colors=1
+    log::debug "Colors forcefuly enabled"
+}
+
 log::debug() {
     local pid=$BASHPID
     if [ "$log__debug" = "1" ] || [ "$DEBUG" = "1" ];then
-        echo -e "\e[90m$(printf "%-6s %-30s" "$pid" "${FUNCNAME[1]}"): $*\e[0m" >&2
+        if [ "$log__colors" = "1" ];then
+            echo -e "\e[90m$(printf "%-6s %-30s" "$pid" "${FUNCNAME[1]}"): $*\e[0m" >&2
+        elif [ "$log__colors" = "-1" ];then
+            log::detect_colors
+            log::debug "$@"
+        else
+            echo -e "[DEBUG  ] $(printf "%-6s %-30s" "$pid" "${FUNCNAME[1]}"): $*" >&2
+        fi
     fi
 }
 
@@ -22,18 +48,51 @@ log::panic() {
     stack::print 1 1
 }
 
+log::fatal() {
+    log::error "$*"
+    exit 1
+}
+
 log::success() {
-    echo -e "\e[32m$*\e[0m" >&2
+    if [ "$log__colors" = "1" ];then
+        echo -e "\e[32m$*\e[0m" >&2
+    elif [ "$log__colors" = "-1" ];then
+        log::detect_colors
+        log::success "$@"
+    else
+        echo -e "[SUCCESS] $*" >&2
+    fi
 }
 
 log::info() {
-    echo -e "\e[36m$*\e[0m" >&2
+    if [ "$log__colors" = "1" ];then
+        echo -e "\e[36m$*\e[0m" >&2
+    elif [ "$log__colors" = "-1" ];then
+        log::detect_colors
+        log::info "$@"
+    else
+        echo -e "[INFO   ] $*" >&2
+    fi
 }
 
 log::error() {
-    echo -e "\e[31m$*\e[0m" >&2
+    if [ "$log__colors" = "1" ];then
+        echo -e "\e[31m$*\e[0m" >&2
+    elif [ "$log__colors" = "-1" ];then
+        log::detect_colors
+        log::error "$@"
+    else
+        echo -e "[ERROR  ] $*" >&2
+    fi
 }
 
 log::warn() {
-    echo -e "\e[33m$*\e[0m" >&2
+    if [ "$log__colors" = "1" ];then
+        echo -e "\e[33m$*\e[0m" >&2
+    elif [ "$log__colors" = "-1" ];then
+        log::detect_colors
+        log::warn "$@"
+    else
+        echo -e "[WARN   ] $*" >&2
+    fi
 }
diff --git a/stack.bash b/stack.bash
index f22806a..5fc15ef 100644
--- a/stack.bash
+++ b/stack.bash
@@ -5,6 +5,10 @@ stack::print() {
     set +o xtrace
     local code="${1:-1}"
     local up=${2:-0}
+    # Ignore errors detected in bashdb
+    if [[ ${FUNCNAME[$up+1]} == _Dbg_* ]];then
+        return
+    fi
     echo -e "\n\e[91mRuntime failure at ${BASH_SOURCE[$up+1]}:${BASH_LINENO[$up]} exit code $err\n"
     stack::point_line "${BASH_SOURCE[$up+1]}" "${BASH_LINENO[$up]}"
     if [ ${#FUNCNAME[@]} -gt $((up+2)) ];then
@@ -41,6 +45,7 @@ stack::point_line() {
 
 trap stack::print ERR
 set -o errtrace
+set -E
 
 import traps
 traps::add_err_trap "stack::print 1 1"
diff --git a/test.sh b/test.sh
index 4f9ea42..172248e 100755
--- a/test.sh
+++ b/test.sh
@@ -10,6 +10,7 @@ import dirdb
 import tmp
 import installer
 import daemon
+import cli
 
 test_fails() {
     unit::assertEq 1 2 "this is error"
@@ -23,3 +24,4 @@ dirdb_test::all
 tmp_test::all
 installer_test::all
 daemon_test::all
+cli_test::all
diff --git a/traps.bash b/traps.bash
index 5009870..30ad2bb 100644
--- a/traps.bash
+++ b/traps.bash
@@ -41,17 +41,18 @@ traps::_handle_int() {
 }
 
 traps::_handle_err() {
+    local err=$?
     log::debug "Handling ERR traps"
     if [ "$traps__err_ignore" = "1" ];then
         return 0
     fi
     for cb in "${traps__err_trap[@]}";do
-        $cb
+        $cb "$err"
     done
 }
 
 traps::_init() {
-    if [ "$traps__set_up" != "$BASHPID" ] && [ -z "$BASH_LIB_UNDER_TEST" ];then
+    if [ "$traps__set_up" = "0" ] && [ -z "$BASH_LIB_UNDER_TEST" ];then
         log::debug "Setting up traps for $BASHPID"
         traps__set_up=$BASHPID
         traps__exit_trap=()
diff --git a/xdg.bash b/xdg.bash
index d9a3e24..5acbd79 100644
--- a/xdg.bash
+++ b/xdg.bash
@@ -27,9 +27,12 @@ xdg::_find_file_in_paths() {
     local filename="$1"
     local paths="$2"
     local directories=()
-    mapfile -d' ' directories <<< "$paths"
+    mapfile -d':' -t directories <<< "$paths"
     for dir in "${directories[@]}";do
-        if [ -d "$dir/$filename" ];then
+        dir=$(echo -n "$dir"|tr -d "\n")
+        log::debug "looking for $dir/$filename..."
+        if [ -e "$dir/$filename" ];then
+            log::debug "found $dir/$filename"
             echo -n "$dir/$filename"
             return
         fi
@@ -50,7 +53,3 @@ xdg::find_config_file() {
     xdg::_find_file_in_paths "$filename" "$config_dirs"
 }
 
-xdg_test::test_find_data_file() {
-    XDG_DATA_DIRS=
-}
-