main: resolve empty "HOSTNAME" [originally: contrib: add "histdb"]

ble-edit.sh

@@ -962,12 +962,12 @@ function ble-edit/draw/trace.impl {
 ## called by ble-edit-initialize
 function ble-edit/prompt/initialize {
   # hostname
-  _ble_edit_prompt__string_H=${HOSTNAME}
-  if local rex='^[0-9]+(\.[0-9]){3}$'; [[ $HOSTNAME =~ $rex ]]; then
+  _ble_edit_prompt__string_H=${HOSTNAME:-$_ble_base_env_HOSTNAME}
+  if local rex='^[0-9]+(\.[0-9]){3}$'; [[ $_ble_edit_prompt__string_H =~ $rex ]]; then
     # IPv4 の形式の場合には省略しない
-    _ble_edit_prompt__string_h=$HOSTNAME
+    _ble_edit_prompt__string_h=$_ble_edit_prompt__string_H
   else
-    _ble_edit_prompt__string_h=${HOSTNAME%%.*}
+    _ble_edit_prompt__string_h=${_ble_edit_prompt__string_H%%.*}
   fi
 
   # tty basename
@@ -978,7 +978,7 @@ function ble-edit/prompt/initialize {
   _ble_edit_prompt__string_s=${0##*/}
 
   # user
-  _ble_edit_prompt__string_u=${USER}
+  _ble_edit_prompt__string_u=${USER:-$_ble_base_env_USER}
 
   # bash versions
   ble/util/sprintf _ble_edit_prompt__string_v '%d.%d' "${BASH_VERSINFO[0]}" "${BASH_VERSINFO[1]}"

ble.pp

@@ -214,12 +214,22 @@ function ble/.check-environment {
   fi
 
   if [[ ! $USER ]]; then
-    echo "ble.sh: Insane environment: \$USER is empty." >&2
-    if type id &>/dev/null; then
-      export USER=$(id -un)
-      echo "ble.sh: modified USER=$USER" >&2
+    ble/util/print "ble.sh: Insane environment: \$USER is empty." >&2
+    if USER=$(id -un 2>/dev/null) && [[ $USER ]]; then
+      export USER
+      ble/util/print "ble.sh: modified USER=$USER" >&2
     fi
   fi
+  _ble_base_env_USER=$USER
+
+  if [[ ! $HOSTNAME ]]; then
+    ble/util/print "ble.sh: suspicious environment: \$HOSTNAME is empty."
+    if HOSTNAME=$(uname -n 2>/dev/null) && [[ $HOSTNAME ]]; then
+      export HOSTNAME
+      ble/util/print "ble.sh: fixed HOSTNAME=$HOSTNAME" >&2
+    fi
+  fi
+  _ble_base_env_HOSTNAME=$HOSTNAME
 
   # 暫定的な ble/bin/$cmd 設定
   ble/bin/.default-utility-path "${_ble_init_posix_command_list[@]}"