在一堆行中添加一些文本 [英] add some text to a bunch of lines

问题描述

第一个命令确实按预期工作，但第二个命令没有.我想在开头或结尾添加一些文字.

The first command does work as expected but not the second one. I want to add some text either at the beginning or the end.

# grep `date +'%y%m%d'` /var/log/mysqld.log
100101 10:56:00  mysqld started
100101 10:56:02  InnoDB: Started; log sequence number 1 2052750649

# sed 's/^/computer /g' < grep `date +'%y%m%d'` /var/log/mysqld.log
bash: grep: No such file or directory

# expected output
computer 100101 10:56:00  mysqld started
computer 100101 10:56:02  InnoDB: Started; log sequence number 1 2052750649

推荐答案

当您使用输入重定向编写它时，它会在当前目录中查找名为 grep 的文件并尝试读取它的内容，而不是执行它.您需要改用管道:

As you wrote it with input redirection, it looks for a file called grep in the current directory and tries to read its contents, not execute it. You need to use a pipe instead:

grep `date +'%y%m%d'` /var/log/mysqld.log | sed 's/^/computer /'

我还从您的 sed 中删除了g"修饰符，因为它完全没有必要.

I also removed the 'g' modifier from your sed as it is completely unnecessary.

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