Shell Programming and Scripting

Figure what out? What, exactly, are you trying to do?

We could show you far less convoluted ways if we knew your intent!

The <<< way works in BASH and only BASH, this should work in any shell:

Code:

read A B C <<EOF
string1 string2 string3
EOF

This is called a "here document" and allows you to put variables and text inside it.

This works for any variable. VARIABLE=whatever command temporarily sets a variable for the duration of the line.

I figured out what you meant by "without ;"

Again though, this isn't something special -- this works for any command. It sets and exports a variable, any variable, only for a single line. You can do

Code:

HTTP_PROXY="proxy:port" wget ...

if you want wget to use a certain proxy, for example.

I am trying to parse a string like "one:two:three:four" into 4 variables. Should be super simple but I ran into that subshell issue. It needs to be robust so that for "::three:" the first two and 4th variable are null.
I think I have it now.

Is this still convoluted?

Code:

IFS=":" read var1 var2 var3 var4 < <(echo "$string")

As an added benefit it is robust against missing delimiters.

Mike

---------- Post updated at 10:58 AM ---------- Previous update was at 10:51 AM ----------

I guess I never knew that variable assignments don't need ; to be on the same line:

Code:

$ a=1 b=2; echo $a; echo $b
1
2

That was a gap in my knowledge.

Mike

And where do you get this string? Perhaps it could be parsed in the first place instead of later.

Actually, I didn't know that either.

That's something totally different from what I was showing you -- temporary assignments:

Code:

VAR="a" echo asdf
echo $VAR

The second 'echo' doesn't find the value of VAR because it was set for only that line.

(You can't echo $VAR in that line, either, since the line gets evaluated before the value of VAR exists. It's useful for built-in variables, and things you want to export.)

I had never hears of temporary assignments. Thanks again.

It is a common way to set specify a variable local to a command. But of course it only works if a command actually uses the variable

Here is list of environment variables that the read command can use:
read: environment variables

The LANG/LC locale environment variables are used by more utilities...

since you're using bash I'd say <<< "$string" is a much better option than < <(echo "$string").

Code:

$ IFS=: read -raa <<< "$PATH"
$ declare -p a
declare -a a='([0]="/home/mute/bin" [1]="/usr/local/bin" [2]="/usr/bin" [3]="/bin" [4]="/usr/local/games" [5]="/usr/games")'