1 files changed, 111 insertions, 0 deletions
diff --git a/src/cmd/ksh93/fun/pushd b/src/cmd/ksh93/fun/pushd
new file mode 100755
index 0000000..1bc9346
--- /dev/null
+++ b/src/cmd/ksh93/fun/pushd
@@ -0,0 +1,111 @@
+#
+# DIRECTORY MANIPULATION FUNCTIONS PUSHD, POPD AND DIRS
+#
+# Uses global parameters _push_max _push_top _push_stack
+integer _push_max=100 _push_top=100
+# Display directory stack -- $HOME displayed as ~
+function dirs
+{
+    typeset dir="${PWD#$HOME/}"
+    case $dir in
+    $HOME)
+        dir=\~
+        ;;
+    /*) ;;
+    *)  dir=\~/$dir
+    esac
+    print -r - "$dir ${_push_stack[@]}"
+}
+
+# Change directory and put directory on front of stack
+function pushd
+{
+    typeset dir= type=0
+    integer i
+    case $1 in
+    "") # pushd
+        if    ((_push_top >= _push_max))
+        then  print pushd: No other directory.
+              return 1
+        fi
+        type=1 dir=${_push_stack[_push_top]}
+        ;;
+    +[1-9]|+[1-9][0-9]) # pushd +n
+        integer i=_push_top$1-1
+        if    ((i >= _push_max))
+        then  print pushd: Directory stack not that deep.
+              return 1
+        fi
+        type=2 dir=${_push_stack[i]}
+        ;;
+    *)  if    ((_push_top <= 0))
+        then  print pushd: Directory stack overflow.
+              return 1
+        fi
+    esac
+    case $dir in
+    \~*)   dir=$HOME${dir#\~}
+    esac
+    cd "${dir:-$1}" > /dev/null || return 1
+    dir=${OLDPWD#$HOME/}
+    case $dir in
+    $HOME)
+        dir=\~
+        ;;
+    /*) ;;
+    *)  dir=\~/$dir
+    esac
+    case $type in
+    0)  # pushd name
+        _push_stack[_push_top=_push_top-1]=$dir
+        ;;
+    1)  # pushd
+        _push_stack[_push_top]=$dir
+        ;;
+    2)  # push +n
+        type=${1#+} i=_push_top-1
+        set -- "${_push_stack[@]}" "$dir" "${_push_stack[@]}"
+        shift $type
+        for dir
+        do  (((i=i+1) < _push_max)) || break
+            _push_stack[i]=$dir
+        done
+    esac
+    dirs
+}
+
+# Pops the top directory
+function popd
+{
+    typeset dir
+    if    ((_push_top >= _push_max))
+    then  print popd: Nothing to pop.
+          return 1
+    fi
+    case $1 in  
+    "")
+        dir=${_push_stack[_push_top]}
+        case $dir in
+        \~*)   dir=$HOME${dir#\~}
+        esac
+        cd "$dir" || return 1
+        ;;
+    +[1-9]|+[1-9][0-9])
+        typeset savedir
+        integer i=_push_top$1-1
+        if    ((i >= _push_max))
+        then  print pushd: Directory stack not that deep.
+              return 1
+        fi
+        while ((i > _push_top))
+        do _push_stack[i]=${_push_stack[i-1]}
+              i=i-1
+        done
+        ;;
+    *)  print pushd: Bad directory.
+        return 1
+    esac
+    unset '_push_stack[_push_top]'
+    _push_top=_push_top+1
+    dirs
+}