diff --git a/sequencer.sh b/sequencer.sh
index e520d66..feecd60 100755
--- a/sequencer.sh
+++ b/sequencer.sh
@@ -149,7 +149,7 @@ sequencer.sh global variables:
     1 - Show time stamps before log outputs
  \${sqr_args}
     String of all given options
- \$SEQ_CONFIG_HOME
+ \${seq_configRoot}
     Path to user specific seq configuration directory
  \${seq_configFile}
     Path to user specific seq configuration file
@@ -161,10 +161,14 @@ sequencer.sh build-in functions:
 USAGE_API
   echo -e "${col_green} root${col_off}"
   cat <<USAGE_API
+    Returns true if current user is root.
+    e.g. root || echo "Not root"
 
 USAGE_API
   echo -e "${col_green} running${col_off}"
   cat <<USAGE_API
+    Returns true if same script already runs.
+    e.g. running && exit 1
 
 USAGE_API
   echo -e "${col_green} exists [OPTIONS] [ELEMENT]${col_off}"
@@ -177,26 +181,32 @@ USAGE_API
 USAGE_API
   echo -e "${col_green} quiet${col_off}"
   cat <<USAGE_API
+    Returns true if seq runs non-interactive (-q|-qq).
 
 USAGE_API
   echo -e "${col_green} silent${col_off}"
   cat <<USAGE_API
+    Returns true if seq runs interactive.
 
 USAGE_API
   echo -e "${col_green} dry${col_off}"
   cat <<USAGE_API
+    Returns true if seq runs in dry-run mode (-d)
 
 USAGE_API
   echo -e "${col_green} verbose${col_off}"
   cat <<USAGE_API
+    Returns true if seq runs in verbose mode (-v)
 
 USAGE_API
   echo -e "${col_green} contextHelp${col_off}"
   cat <<USAGE_API
+    Returns true if current output is only for help purposes.
 
 USAGE_API
   echo -e "${col_green} contextExe${col_off}"
   cat <<USAGE_API
+    Returns true if current output is in execution mode.
 
 USAGE_API
   echo -e "${col_green} confirm [OPTIONS] [QUESTION]${col_off}"
@@ -287,7 +297,7 @@ USAGE_API
     dry-run is not applied in this function! The executed step is responsible.
 
 USAGE_API
-  echo -e "${col_green} outColor [FOREGROUND COLOR] [BACKGROUND COLOR]${col_off}"
+  echo -e "${col_green} color [FOREGROUND COLOR] [BACKGROUND COLOR]${col_off}"
   cat <<USAGE_API
     Set output color permanently until reset.
     No argument or unknown foreground color restores shell default (reset).
@@ -295,16 +305,12 @@ USAGE_API
       [COLOR]: black, red, green, yellow, blue, magenta, cyan, white
 
 USAGE_API
-  echo -e "${col_green} echoerr [...]${col_off}"
+  echo -e "${col_green} info|warning|error|debug [OPTIONS] [STRING]${col_off}"
   cat <<USAGE_API
-    echo to stderr
-      [...] : all parameter are forwarded to echo
-
-USAGE_API
-  echo -e "${col_green} echoseq [...]${col_off}"
-  cat <<USAGE_API
-    echo to stdout if sequencer output is not suppressed
-      [...] : all parameter are forwarded to echo
+    Output [STRING] (can be multiline) to stdout according to log level.
+      [OPTIONS]
+        -a  : Append [STRING] skipping leading " [ ] " prefix
+        -e  : Output to stderr
 
 USAGE_API
   echo -e "${col_green} echoinfo [...]${col_off}"
@@ -321,7 +327,7 @@ USAGE_API
       [...] : no parameter are forwared to echo
 
 USAGE_API
-  echo -e "${col_green} endCheckEmpty <VARIABLENAME> [DESCRIPTION]${col_off}"
+  echo -e "${col_green} endIfEmpty <VARIABLENAME> [DESCRIPTION]${col_off}"
   cat <<USAGE_API
     exit 666 if variable is empty
       <VARIABLENAME> : Name without \$
@@ -349,11 +355,6 @@ USAGE_API
       [MESSAGE]
         String which is displayed in the error output
 
-USAGE_API
-  echo -e "${col_green} exitIfRunning${col_off}"
-  cat <<USAGE_API
-    End sequence if an instance of it is still running
-
 USAGE_API
 }