I'm trying to split key value pairs (around an = sign) which I then use to edit a config file, using bash. But I need an alternative to the <<< syntax for IFS.
The below works on my host system, but when i log in to my ubuntu virtual machine through ssh I have the wrong bash version. Whatever I try, <<< fails. (I am definitely calling the right version of bash at the top of the file, using #!/bin/bash (and I've tried #!/bin/sh etc too)).
I know I can use IFS as follows on my host mac os x system:
var="word=hello"
IFS='=' read -a array <<<"$var"
echo ${array[0]} ${array[1]]}
#alternative -for calling through e.g. sh file.sh param=value
for var in "$@"
do
IFS='=' read -a array <<<"$var"
echo ${array[0]} ${array[1]]}
done
#alternative
IFS='=' read -ra array <<< "a=b"
declare -p array
echo ${array[0]} ${array[1]}
But this doesn't work on my vm.
I also know that I can should be able to switch the <<< syntax through backticks, $() or echo "$var" | ... but I can't get it to work - as follows:
#Fails
IFS='=' read -ra myarray -d '' <"$var"
echo ${array[0]} ${array[1]]}
#Fails
echo "$var" | IFS='=' read -a array
echo ${array[0]} ${array[1]]}
#fails
echo "a=b" | IFS='=' read -a array
declare -p array
echo ${array[0]} ${array[1]}
Grateful for any pointers as I'm really new to bash.
Your attempts have been confounded because you have to use the variable in the same sub-shell as read.
$ echo 'foo=bar' | { IFS='=' read -a array; echo ${array[0]}; }
foo
And if you want your variable durable (ie, outside the sub-shell scope):
$ var=$(echo 'foo=bar' | { IFS='=' read -a array; echo ${array[0]}; })
$ echo $var
foo
Clearly, it isn't pretty.
Update: If -a is missing, that suggests you're out of the land of arrays. You can try parameter substitution:
str='foo=bar'
var=${str%=*}
val=${str#*=}
And if that doesn't work, fall back to good ole cut:
str='foo=bar'
var=$(echo $str | cut -f 1 -d =)
val=$(echo $str | cut -f 2 -d =)