examples/scripts.v2/cdhist.bash

   1 #! /bin/bash
   2 #
   3 # cdhist - cd replacement with a directory stack like pushd/popd
   4 #
   5 # usage: cd [-l] [-n] [-] [dir]
   6 #
   7 # options:
   8 #       -l      print the cd directory stack, one entry per line
   9 #       -       equivalent to $OLDPWD
  10 #       -n      cd to nth directory in cd directory stack
  11 #       -s      cd to first directory in stack matching (substring) `s'
  12 #
  13 # arguments:
  14 #       dir     cd to dir and push dir onto the cd directory stack
  15 #
  16 # If the new directory is a directory in the stack and the options selected
  17 # it (-n, -s), the new working directory is printed
  18 #
  19 # If the variable CDHISTFILE is set, the cd directory stack is loaded from
  20 # and written to $CDHISTFILE every time `cd' is executed.
  21 #
  22 # Note: I got this off the net somewhere; I don't know the original author
  23 #
  24 # Chet Ramey
  25 # chet@po.cwru.edu
  26
  27 _cd_print()
  28 {
  29         echo -e "$@"
  30 }
  31
  32 cd()
  33 {
  34         typeset -i cdlen i
  35         typeset t
  36
  37         if [ $# -eq 0 ]
  38         then
  39                 set -- $HOME
  40         fi
  41
  42         if [ "$CDHISTFILE" ] && [ -r "$CDHISTFILE" ] # if directory history exists
  43         then
  44                 typeset CDHIST
  45                 i=-1
  46                 while read -r t                 # read directory history file
  47                 do
  48                         CDHIST[i=i+1]=$t
  49                 done <$CDHISTFILE
  50         fi
  51
  52         if [ "${CDHIST[0]}" != "$PWD" ] && [ -n "$PWD" ]
  53         then
  54                 _cdins                          # insert $PWD into cd history
  55         fi
  56
  57         cdlen=${#CDHIST[*]}                     # number of elements in history
  58
  59         case "$@" in
  60         -)                                      # cd to new dir
  61                 if [ "$OLDPWD" = "" ] && ((cdlen>1))
  62                 then
  63                         '_cdprint' ${CDHIST[1]}
  64                         builtin cd ${CDHIST[1]}
  65                         pwd
  66                 else
  67                         builtin cd "$@"
  68                         # pwd
  69                 fi
  70                 ;;
  71         -l)                                     # _cdprint directory list
  72                 ((i=cdlen))
  73                 while (((i=i-1)>=0))
  74                 do
  75                         num=$i
  76                         '_cdprint' "$num ${CDHIST[i]}"
  77                 done
  78                 return
  79                 ;;
  80         -[0-9]|-[0-9][0-9])                     # cd to dir in list
  81                 if (((i=${1#-})<cdlen))
  82                 then
  83                         '_cdprint' ${CDHIST[i]}
  84                         builtin cd ${CDHIST[i]}
  85                         pwd
  86                 else
  87                         builtin cd $@
  88                         # pwd
  89                 fi
  90                 ;;
  91         -*)                                     # cd to matched dir in list
  92                 t=${1#-}
  93                 i=1
  94                 while ((i<cdlen))
  95                 do
  96                         case ${CDHIST[i]} in
  97                         *$t*)
  98                                 '_cdprint' ${CDHIST[i]}
  99                                 builtin cd ${CDHIST[i]}
 100                                 pwd
 101                                 break
 102                                 ;;
 103                         esac
 104                         ((i=i+1))
 105                 done
 106                 if ((i>=cdlen))
 107                 then
 108                         builtin cd $@
 109                         # pwd
 110                 fi
 111                 ;;
 112         *)                                      # cd to new dir
 113                 builtin cd $@
 114                 # pwd
 115                 ;;
 116         esac
 117
 118         _cdins                                  # insert $PWD into cd history
 119
 120         if [ "$CDHISTFILE" ]
 121         then
 122                 cdlen=${#CDHIST[*]}             # number of elements in history
 123
 124                 i=0
 125                 while ((i<cdlen))
 126                 do
 127                         echo ${CDHIST[i]}       # update directory history
 128                         ((i=i+1))
 129                 done >$CDHISTFILE
 130         fi
 131 }
 132
 133 _cdins()                                        # insert $PWD into cd history
 134 {                                               # meant to be called only by cd
 135         typeset -i i
 136
 137         i=0
 138
 139         while (( i < ${#CDHIST[*]} ))           # see if dir is already in list
 140         do
 141                 if [ "${CDHIST[$i]}" = "$PWD" ]
 142                 then
 143                         break
 144                 fi
 145                 ((i=i+1))
 146         done
 147
 148         if (( i>22 ))                           # limit max size of list
 149         then
 150                 i=22
 151         fi
 152
 153         while (((i=i-1)>=0))                    # bump old dirs in list
 154         do
 155                 CDHIST[i+1]=${CDHIST[i]}
 156         done
 157
 158         CDHIST[0]=$PWD                          # insert new directory in list
 159 }
 160
 161 # examples
 162 shopt -s expand_aliases
 163
 164 # go to known place before doing anything
 165 cd /
 166
 167 echo CDHIST: "${CDHIST[@]}"
 168 for dir in /tmp /bin - -2 -l
 169 do
 170         cd $dir
 171         echo CDHIST: "${CDHIST[@]}"
 172         echo PWD: $PWD
 173
 174 done
 175
 176 exit 0