无法将 grep 用于命令并执行 shell 脚本？

Question

我创建了一个 shell 脚本来从名为 elist.txt 的文件中执行 5 个命令

ps -ef | grep user | grep 'process -s 9000' | cut -c -15 | cut -c 10-
ps -ef | grep user | grep 'process -s 9001' | cut -c -15 | cut -c 10-
ps -ef | grep user | grep 'process -s 9002' | cut -c -15 | cut -c 10-
ps -ef | grep user | grep 'process -s 9003' | cut -c -15 | cut -c 10-

shell脚本如下

export PATH="/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/home/user/.local/bin:/home/user/bin"
input="/home/user/script/list.txt"
while IFS= read -r line
do
echo $($line)
done < "$input"

output：

error: garbage option

Usage:
 ps [options]

 Try 'ps --help <simple|list|output|threads|misc|all>'
  or 'ps --help <s|l|o|t|m|a>'
 for additional help text.

For more details see ps(1).

Answer 1

我会将此脚本与 eval 一起使用，这是此答案https://stackoverflow.com/a/6002329/6778826中描述的类似解决方案

export PATH="/bin:/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/home/user/.local/bin:/home/user/bin"
input="/home/user/script/list.txt"
while read -r line
do
  eval "$line"
done <$input

Answer 2

你也可以这样做。 人们通常根本不推荐使用eval 。

export PATH="/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/home/user/.local/bin:/home/user/bin"
input="/home/user/script/list.txt"
while IFS= read -r line
do
bash -c "$line"
done < "$input"

问候！