Bash : Concatenate variables containing strings n columns by n columns

Question

I have 2 variables containing the same number of information, here 1 line with n=3 columns (I mean separated by a space)

var1='abc def ghi'
var2='klm nop qrs'

I would like the output to be the concatenated result with one line and 3 columns, with the following pattern :

abcklm defnop ghiqrs

I tried with a $(paste <echo $var1) <(echo $var2) -d '') But it does the same as $var1$var2 .

The pr -ms' ' $var1 $var2 doesn't work, it's like it is waiting for a file rather than a variable

Answer 1

paste -d "" <(tr ' ' '\n' <<<"$var1") <(tr ' ' '\n' <<<"$var2") | paste -sd " "

• convert the space-separated variables into newline-separated files.
• join the files.
• then join the output lines.

Documentation:

• 3.5.6 Process Substitution
• 3.6.7 Here Strings
• man pages for tr and paste