I am inside a docker container build atop of the image alpine:3.6 and I am trying to find if a directory exists. I get te error,

find: './proc/1/map_files': Permission denied

This is the commands I used for the search,

root@5f4776320924:/# ls
bin   docker-entrypoint-initdb.d  home   media  proc  sbin  tmp
boot  entrypoint.sh       lib    mnt    root  srv   usr
dev   etc             lib64  opt    run   sys   var
root@5f4776320924:/# find . -type d | grep "adminer"
find: './proc/1/map_files': Permission denied

If I try to use the root using $ su -, I only get inside the root folder and I wasn't able to perform the search.

What's the issue here? I think the searching command is correct.

1 Answer 1


Your command is correct (although a bit overcomplicated, using the name option of find instead of grepping would be better).

find / -type d -name adminer

/proc is a very special filesystem which contains information about running processes. Therefore, not everything is accessible (not even to root). The Linux Documentation Project has a good writeup:


  • I have checked the page you mentioned, but, this is kind of over the edge. What do we need to do to find a directory in the Linux container?
    – Arefe
    Mar 19, 2019 at 9:57
  • The command is correct! If it doesn't return something, then the directory does not exist. You should use find / -type d -name adminer (and if you don't want to see the error messages, add 2>/dev/null)
    – Panki
    Mar 19, 2019 at 10:12
  • 2
    still, it would've been interesting to know why /proc/1/map_files/ is not readable by the "root" from a docker container. Saying that /proc is "very special" isn't very edifying -- I'm very special, too ;-)
    – user313992
    Mar 19, 2019 at 12:11

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