17 comment

1. Nice one ;)

2. Excellent info.

3. how to clean the array? ;d

   1. Here’s a quick flush:
      NUM=${#a[@]}; for ((i=0;i<${NUM};i++)); do a[${i}]=''; done

      And a for a quick scan, you can do the following either before or after:
      COUNT=0; while [ ${COUNT} -lt ${#a[@]} ]; do echo ${a[${COUNT}]}; COUNT=$((COUNT+1)); done

4. Hi!
   I think that this example is bad.
   I would do this without a block .

   #!/bin/bash

   NAMESERVERS=”ns1.nixcraft.net. ns2.nixcraft.net. ns3.nixcraft.net.”
   for i in $NAMESERVERS; do
   echo “$i”
   done

   1. That only works if you have no spaces.

      1. The way it’s done in the post only works when using bash. This is a more POSIX-compatible way of making it work. You can also change the element-separator character to something different than the space, using the variabe IFS.

5. Problems,

   a[2]=222
   echo ${#a[@]}
   1

   Thus this is the lenght of the array, not the index of the last element.

   Try instead:
   for i in “${a[@]}”; do echo $i; done

   Some further ideas may be found at
   http://tldp.org/LDP/abs/html/arrays.html
   http://www.linuxjournal.com/content/bash-arrays

   Best Regards,
   Raymond

   1. Well yes, ${#a[@]} pretty much spits out the the number of elements in the array, like the document here said… notice that it’s plainly used as tlen which is the length of the array?

      you could do it a million different ways…

      NUM=${a[@]}
      for ((i=0;i<${NUM};i++)); do echo ${a[${NUM}]}; done

      or:

      COUNT=0; while [ ${COUNT} -lt ${#a[@]} ]; do echo ${a[${COUNT}]}; COUNT=$((COUNT+1)); done

      We could go on and on, since there's more than one way to skin a cat.

6. Good points on handling a possibly sparse array, Raymond, but the example is pretty useful if you load the array yourself. Also note that you don’t need to use a variable to store the array length:

   for (( i = 0 ; i < ${#my_array[@]} ; i++ )) do; echo "${my_array[i]}"; done

   Note the implementations of BASH I am using don't require "$i" as the index of the array, they work fine with just "i". This only seems to work with single character length index variable names though, like "i", not with, for example, "index". YMMV.

   Regards,
   Stuart

7. 1.Write a Linux shell Script to count the Number of user accounts both normal and special or privileged user user accounts on the system.
   2.Write an interactive Linux shell script to test whether a file is (a). Read Permission set. (b). Execution permission set (c). Is a non empty file (d). A regular file (e). Ia a directory.

8. lol @ all the bikeshedding syntax scholars here. Ok, your voice has been heard, move along idiots.

   1. It’s called sharing knowledge. If you don’t like it, move along.

9. Dan I know this is an older thread but I found this and your information was very helpful to me. Unfortunately there are not enough people in the world like you and more like Ryan.

   Thanks again!

10. Hi, Sorry i know this is an old thread!

    I need a help!

    for i in `seq 1 ${#DEV[@]}` ; do
      echo "DEV- ${DEV[$i]} ${DEV_DS[$i]} " >> $REPORT1

    ${#DEV[@]} –> this represents the length of the array

    If I want to go to the second last element of the array , what can I write in place of ${#DEV[@]} ?

    1. If ${#DEV[@]} is the last element then just decrement it to get the second last element.

       1. Old thread; yep i’ve used below;

          $(( ${#arry[@]}-2 ))

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