pathmunge /usr/local/linuxNode/node-v16.18.0-linux-x64/bin after  # /etc/profile   # System wide environment and startup programs, for login setup # Functions and aliases go in /etc/bashrc   # It's NOT a good idea to change this file unless you know what you # are doing. It's much better to create a custom.sh shell script in # /etc/profile.d/ to make custom changes to your environment, as this # will prevent the need for merging in future updates. #pathmunge 是Linux 函數   pathmunge () {     case ":${PATH}:" in         *:"$1":*)             ;;         *)             if [ "$2" = "after" ] ; then                 PATH=$PATH:$1             else                 PATH=$1:$PATH             fi     esac }     if [ -x /usr/bin/id ]; then     if [ -z "$EUID" ]; then         # ksh workaround         EUID=`/usr/bin/id -u`         UID=`/usr/bin/id -ru`     fi     USER="`/usr/bin/id -un`"     LOGNAME=$USER     MAIL="/var/spool/mail/$USER" fi   # Path manipulation  #$EUID 是全局變量 判斷用戶是否具有權限 if [ "$EUID" = "0" ]; then     pathmunge /usr/sbin     pathmunge /usr/local/sbin else     pathmunge /usr/local/sbin after     pathmunge /usr/sbin after fi   HOSTNAME=`/usr/bin/hostname 2>/dev/null` HISTSIZE=1000 if [ "$HISTCONTROL" = "ignorespace" ] ; then     export HISTCONTROL=ignoreboth else     export HISTCONTROL=ignoredups fi   #使用 pathmunge 函數  pathmunge /usr/local/linuxNode/node-v16.18.0-linux-x64/bin after   export PATH USER LOGNAME MAIL HOSTNAME HISTSIZE HISTCONTROL   # By default, we want umask to get set. This sets it for login shell # Current threshold for system reserved uid/gids is 200 # You could check uidgid reservation validity in # /usr/share/doc/setup-*/uidgid file if [ $UID -gt 199 ] && [ "`/usr/bin/id -gn`" = "`/usr/bin/id -un`" ]; then     umask 002 else     umask 022 fi   for i in /etc/profile.d/*.sh /etc/profile.d/sh.local ; do     if [ -r "$i" ]; then         if [ "${-#*i}" != "$-" ]; then              . "$i"         else             . "$i" >/dev/null         fi     fi done   unset i unset -f pathmunge