推送/弹出ksh？

Question

在KSH的命令中是否有相当于bash pushd/popd的内置版本？

对于那些不知道bash中pushd和popd是什么的人,这里是手册页中的描述

   pushd [-n] [dir]
   pushd [-n] [+n] [-n]
          Adds  a directory to the top of the directory stack, or rotates
          the stack, making the new top of the stack the current  working
          directory.   With  no arguments, exchanges the top two directo-
          ries and returns 0, unless the directory stack is empty.


   popd [-n] [+n] [-n]
          Removes entries from the directory stack.  With  no  arguments,
          removes  the top directory from the stack, and performs a cd to
          the new top directory.  Arguments, if supplied, have  the  fol-
          lowing meanings:

谢谢

Answer 1

当我发现ksh不包括这些时,我写了自己的.我把它放进去~/bin/dirstack.ksh,我的.kshrc文件包括这样:

. ~/bin/dirstack.ksh

以下是内容dirstack.ksh:

# Implement a csh-like directory stack in ksh
#
# environment variable dir_stack contains all directory entries except
# the current directory

unset dir_stack
export dir_stack


# Three forms of the pushd command:
#    pushd        - swap the top two stack entries
#    pushd +3     - swap top stack entry and entry 3 from top
#    pushd newdir - cd to newdir, creating new stack entry

function pushd
{
   sd=${#dir_stack[*]}  # get total stack depth
   if [ $1 ] ; then
      if [ ${1#\+[0-9]*} ] ; then
         # ======= "pushd dir" =======

         # is "dir" reachable?
         if [ `(cd $1) 2>/dev/null; echo $?` -ne 0 ] ; then
            cd $1               # get the actual shell error message
            return 1            # return complaint status
         fi

         # yes, we can reach the new directory; continue

         (( sd = sd + 1 ))      # stack gets one deeper
         dir_stack[sd]=$PWD
         cd $1
         # check for duplicate stack entries
         # current "top of stack" = ids; compare ids+dsdel to $PWD
         # either "ids" or "dsdel" must increment with each loop
         #
         (( ids = 1 ))          # loop from bottom of stack up
         (( dsdel = 0 ))        # no deleted entries yet
         while [ ids+dsdel -le sd ] ; do
            if [ "${dir_stack[ids+dsdel]}" = "$PWD" ] ; then
               (( dsdel = dsdel + 1 ))  # logically remove duplicate
            else
               if [ dsdel -gt 0 ] ; then        # copy down
                  dir_stack[ids]="${dir_stack[ids+dsdel]}"
               fi
               (( ids = ids + 1 ))
            fi
         done

         # delete any junk left at stack top (after deleting dups)

         while [ ids -le sd ] ; do
            unset dir_stack[ids]
            (( ids = ids + 1 ))
         done
         unset ids
         unset dsdel
      else
         # ======= "pushd +n" =======
         (( sd = sd + 1 - ${1#\+} ))    # Go 'n - 1' down from the stack top
         if [ sd -lt 1 ] ; then (( sd = 1 )) ; fi
         cd ${dir_stack[sd]}            # Swap stack top with +n position
         dir_stack[sd]=$OLDPWD
      fi
   else
      #    ======= "pushd" =======
      cd ${dir_stack[sd]}       # Swap stack top with +1 position
      dir_stack[sd]=$OLDPWD
   fi
}

function popd
{
   sd=${#dir_stack[*]}
   if [ $sd -gt 0 ] ; then
      cd ${dir_stack[sd]}
      unset dir_stack[sd]
   else
      cd ~
   fi
}

function dirs
{
   echo "0: $PWD"
   sd=${#dir_stack[*]}
   (( ind = 1 ))
   while [ $sd -gt 0 ]
   do
      echo "$ind: ${dir_stack[sd]}"
      (( sd = sd - 1 ))
      (( ind = ind + 1 ))
   done
}