ACE/bin/add_rel_link.sh

   1 #!/bin/sh
   2 # This script assumes it is being run by bash
   3
   4 # ======= needed functions ======
   5 # abspath relpath curentpath
   6 abspath ()
   7 {
   8 # treat "./" as a special case
   9 if expr "$1" : '\./' >/dev/null; then
  10   b=`echo $1 | sed 's@\./@@'`
  11   echo $2/$b
  12   return 0
  13 fi
  14 b=$1
  15 a=$2
  16 # for each "../" we remove one directory from the current path
  17 # and leading "../" from the relative path
  18 # until we have the unique part in b and the abs prefix in a
  19 while expr "$b" : '\.\./' >/dev/null
  20 do
  21   b=`echo $b | sed 's@\.\./@@'`
  22   a=`echo $a | sed 's@/[^/]*$@@'`
  23 done
  24 # return the completed absolute path
  25 echo $a/$b
  26 }
  27
  28 # relpath abspath curentpath
  29 relpath ()
  30 {
  31 # take "/" off beginning
  32 a=`echo $1 | sed 's@^/@@'`
  33 # take "/" off beginning and add to end
  34 b=`echo $2 | sed 's@^/@@;s@$@/@'`
  35 while true
  36 do
  37   if [ "$b" = "" ]; then
  38     break;
  39   fi
  40   a1=`echo $a | sed 's@\([^/]*\)/.*@\1@'`
  41   b1=`echo $b | sed 's@\([^/]*\)/.*@\1@'`
  42   if [ "$a1" != "$b1" ]; then
  43     break;
  44   fi
  45   a=`echo $a | sed 's@[^/]*/@@'`
  46   b=`echo $b | sed 's@[^/]*/@@'`
  47 done
  48 # a now has the unique part of the path
  49 c=""
  50 # c will have the required number of "../"'s
  51 while [ "$b" != "" ]
  52 do
  53   c="../$c"
  54   b=`echo $b | sed 's@[^/]*/@@'`
  55 done
  56 # return the completed relative path
  57 echo "$c$a"
  58 }
  59
  60
  61 # ====== MAIN ======
  62 # Assume any relative path passed in is relative to the current directory
  63 # Given $1 is a path to the source file
  64 # Given $2 is a path of the link to be created
  65 # Create a link that has the relative path to the source file
  66 # That is, $1 converted relative to $2
  67 # Check if $1 is absolute or already relative
  68 #echo add_rel_link.sh $1 $2
  69 if expr "$1" : '\/' >/dev/null; then
  70   # The source path is absolute, this is the expected case
  71   # Check if $2 is absolute or relative
  72   if expr "$2" : '\/' >/dev/null; then
  73     # The link path is already absolute, so just use it
  74     lpath=$2
  75   else
  76     # The link path is relative, this is the expected case
  77     # WARNING: don't use $PWD here, it won't work right
  78     # WARNING: pwd may be a shell alias.  Use /bin/pwd.
  79     cur=`/bin/pwd`
  80     lpath=`abspath $2 $cur`
  81   fi
  82   # take name off the end of the dest
  83   ldir=`echo $lpath | sed 's@/[^/]*$@@'`
  84
  85   # If the original path and the ldir do not originate in the same
  86   # directory tree, we should just use absolute paths
  87   if [ "`echo $1 | cut -d/ -f2`" != "`echo $ldir | cut -d/ -f2`" ]; then
  88     spath=$1
  89   else
  90     spath=`relpath $1 $ldir`
  91   fi
  92   # use the completed relative path and the given designation path
  93   echo ln -s $spath $2
  94   ln -s $spath $2
  95 else
  96   # The source path is already relative, so just use it
  97   echo ln -s $1 $2
  98   ln -s $1 $2
  99 fi