使用 Bash 重定向管道中的错误时遇到问题？

Question

ls -lhR /etc/ | egrep *.conf$ >/home/student/total_size.txt 2>/home/student/error.txt

So I used this command to get all.conf files from /etc/ . I want the output in total_size.txt and my errors in error.txt . My output looks good, but the errors won't redirect to error.txt , they appear in my terminal:

ls: cannot open directory '/etc/cups/ssl': Permission denied

I don't know what to do; I tried 2>> instead of 2> but it won't work either.

Answer 1

This happens because ls 's stderr still points to the terminal. You need to wrap pipeline in curly braces, and do the redirection outside. Eg:

{ ls -lhR /etc/ | egrep *.conf$; } >/home/student/total_size.txt 2>/home/student/error.txt

Answer 2

Try this, should do the trick.

ls -lhR /etc/ 2>>/home/student/error.txt | egrep *.conf$ >/home/student/total_size.txt

The errors are generated by ls , not egrep .