[问题求助] Shell脚本怎样按列合并变量？

newswan

两个变量，怎么按列合并，比如，a b 合并成 c
类似 paste

a='
11,12,13
21,22,23
'
b='
14,15,16
24,25,26
'COPY

c='
11,12,13,14,15,16
21,22,23,24,25,26
'COPY

wanghan519

c=$(paste <(echo "$a") <(echo "$b") -d,)COPY