linux-如何正确引用此bash管道以进行监视？

我建立了以下管道：

echo "scale=2;$(cat io | grep wchar | awk '{print $2}')/(1024^3)" | bc

现在,我正在尝试观看.我对Bash的了解确实是临时的,所以我没有成功.尝试过这样的事情：

watch echo "scale=2;$(cat io | grep wchar | awk '{print $2}')/(1024^3)" | bc # I understand why this fails

watch 'echo "scale=2;$(cat io | grep wchar | awk '{print $2}')/(1024^3)" | bc' # Not enough bash understanding to understand why this fails

我究竟做错了什么？

编辑

cat io的样本输出为

rchar: 36713294562
wchar: 36788363400
syscr: 27050
syscw: 2314540
read_bytes: 36709928960
write_bytes: 0
cancelled_write_bytes: 0

解决方法:

问题是关于awk的单引号,您可以通过转义单引号来解决它.

watch 'echo "scale=2;$(cat io | grep wchar | awk '"'"'{print $2}'"'"')/(1024^3)" | bc'

关于如何在单引号内转义单引号,有一个很好的解释“BASH, escaping single-quotes inside of single-quoted strings”