"$()" 或 `` 未正确扩展 shell 脚本中的 linux 命令

Question

我的代码片段有如下回显行：

echo "$(wc -l prov_bulk) provisioning commands found between $t_stmp1 of $(head -1 file_list) till $t_stmp2 of $(tail -1 file_list)"

预期输出：

1054721 provisioning commands found between 2017033023 of 170330.AUG till 2017033102 of 170331.AUG

输出得到：

1054721 prov_bulk provisioning commands found between 2017033023 of 170330.AUG till 2017033102 of 170331.AUG

为什么文件名 "prov_bulk" 也出现了？如何摆脱这个？

Answer 1

只需添加一个 < 即可解决您的问题。重定向省略了文件名。

echo "$(wc -l < prov_bulk) provisioning commands found between $t_stmp1 of $(head -1 file_list) till $t_stmp2 of $(tail -1 file_list)"

"$()" or `` is not properly expanding the linux command in shell script