[SOLVED] get path name from array -> always wants to do math

slackware_newbie · 07-01-2015, 11:36 AM

With the following code

Code:

DIRS[0]=home/mb
DIRS[1]=etc

for i in ${DIRS[@]}
do
  echo ${DIRS[$i]}
done

I always get a "division by zero" error because of the "/" in DIRS[0].

It works if I write

Code:

echo $DIRS[0]

but as soon i use the $i to access the value the bash misinterprets the "/" and wants to do math.

Keith Hedger · 07-01-2015, 11:57 AM

this is because the command '${DIRS[$i]}' expects a number inside the brackets as its an array subscript what you want is

Code:

DIRS[0]=home/mb
DIRS[1]=etc
for i in ${DIRS[@]}
do
 echo $i
done

slackware_newbie · 07-02-2015, 03:22 AM

Now I have this

Code:

#!/bin/bash

TARGET=/media/mb/Elements/DAR20
DATE=`date -I`
DAROPTIONS='-m 0 -z -s 50000M -D -Z "*.gz" -Z "*.bz2" -Z "*.zip" -Z "*.png" -Z "*.7z" -v'

# LOCAL
DIRS[0]=home/mb
EXCLUDES[0]='-P tmp -P VirtualBox\ VMs -P Downloads -P .cache -P .local/share/Trash'

DIRS[1]=etc
EXCLUDES[1]=

for i in ${DIRS[@]}
do
  FILE=$TARGET/"$i"/${DATE}_${y}
  mkdir -p $TARGET/"$i"
  if [ ! -f "$FILE" ]
  then
    dar -R /"$i" -c "$FILE" $DAROPTIONS ${EXCLUDES[$i]}
  else
    PREV=`ls $TARGET/"$i"/*.dar | head -n 1`
    dar -R /"$i" -c "$FILE" -A ${PREV%%.*} $DAROPTIONS ${EXCLUDES[$i]}
  fi
done

And still get division by zero on line 20.

Keith Hedger · 07-02-2015, 07:38 AM

you have done exactly the same as before, you can NOT use a string as a subscript it MUST be nunber.

Keith Hedger · 07-02-2015, 07:31 PM

As I see you have started a new thread with this same script but have fixed the subscript problem I assume you consider this part of the problem solved, so please mark this thread as solved its also good manners to say thanks and post the solution to your problem for the sake of any one else searching the forum with a similar problem.

slackware_newbie · 07-03-2015, 02:09 AM

Sorry about that. You are right.

I solved it like this

Code:

for ((i=0; i<${#DIRS[@]}; i++))
do
  FILE=$TARGET/"${DIRS[$i]}"/${DATE}_${y}
  mkdir -p $TARGET/"${DIRS[$i]}"
  if [ ! -f "$FILE" ]
  then
    dar -R /"${DIRS[$i]}" "${EXCLUDES[$i]}" -c "$FILE" $DAROPTIONS
  else
    PREV=`ls $TARGET/"${DIRS[$i]}"/*.dar | head -n 1`
    dar -R /"${DIRS[$i]}" "${EXCLUDES[$i]}" -c "$FILE" -A ${PREV%%.*} $DAROPTIONS
  fi
done