小编Sam*_*jar的帖子

如何在bash子shell中调用echo？这是我想要的行为:

# w=5
# echo $w > /tmp/x
# cat /tmp/x
5

但:

# cmd="echo $w > /tmp/x"
# $cmd
5 > /tmp/x

和:

# $( $cmd )
bash: 5: command not found