Bash split string into array

[the182guy]

Hi,

I have a string which is an IP Address, I want to spli the octets into an array and retrieve the individual octets. Here is what I have got so far:

# create the string IP address
IPSTR="192.168.1.4"

# declare the array
declare -a IPARR

IP_ARR=$(echo $IPSTR | tr "." " ")

# print out the first octet (should be 192). This actually prints out a blank line
echo ${IPARR[0]}

# also tried with quotes, but same result:
echo "${IPARR[0]}"

I can print the entire array out with this line of code:

echo ${IPARR[@]}

I can also loop through the array and print out the octets one by one. But I want to be able to access them directly without having to loop.

Anyone know why it prints out a blank line when I try to access an array element?

[ghostdog74]

ip="192.168.0.1"
IFS="."
set -- $ip
echo "$1,$2,$3,$4"

[the182guy]

Thanks ghostdog, I've seen that method from searching. I was hoping to be able to achieve this by using tr method.

I think it is an issue with the array keys. After the string being split into the array, it doesn't have keys of 0,1,2,3 as I would expect. It does have keys though but I can't see what they are, I know this because when I do a "for in" loop, the data is retrieved.

Perhaps it's the array declaration needing some syntax to say it's a numerical key array.

[Lost_scrib]

# create the string IP address
IPSTR="192.168.1.4"

# declare the array
declare -a IPARR

IPARR=(`echo $IPSTR | tr "." " "`)

# print out the first octet (should be 192). This actually prints out a blank line
echo ${IPARR[0]}

# also tried with quotes, but same result:
echo "${IPARR[0]}"

Works for me...

You should slap yourself...


Or:

1. Read carefully, IP_ARR is not the same as IPARR
2. Array should be initialized with (content1 content2)

3. #! /bin/bash -x

   is useful when debugging your scripts. After your debug process is done, you can remove the -x parameter

[gumaheru]

Don't use a pipe as it causes a new process to be created. Here is your code with a small change. Use "IPARR=(`echo ${IPSTR//./ }`)" instead of "IPARR=(`echo $IPSTR | tr "." " "`)"

# create the string IP address
IPSTR="192.168.1.4"

# declare the array
declare -a IPARR

IPARR=(`echo ${IPSTR//./ }`)

# print out the first octet (should be 192). This actually prints out a blank line
echo ${IPARR[0]}

# also tried with quotes, but same result:
echo "${IPARR[0]}"