What is the correct way to mount an initrd.img file with the "mount" command and the "-o loop" option? I am newbie to Linux and to commands. I tried this:

mount -o loop initrd.img /tmp

This is error: Could you tell me the correct way to use this "mount -o loop" command with this "initrd.img" file? I want to be able to add some files to it.

This might help.

Thank you for the comment. That was useful to provide a link to a web about initrd.

I also found this helpful:

if you wanna do it the simple way, like your original idea; you use mount -t sysfs

for example:

#make a directory to mount on
mkdir temp

#mount the file on temp...
mount -t sysfs /initrd.img /temp -o loop

3 members found this post helpful.

Been a while since that last post, but mcurran's method gave me a different file structure than newtovanilla's helpful link.

How does that work?

sysfs:
block class devices fs kernel power
bus dev firmware hypervisor module

gunzip-cpio:
run lib64 sbin bin lib proc root
sys tmp usr var dev init sysroot etc

I used find and the directories obtained with cpio are not found inside the sysfs mount. A quick search on Google returned a rather confusing explanation of sysfs -confusing as to how it relates to this situation.

This is now a question on theory, in practice the gunzip-cpio combo is just what I needed so thanks for that link.

Note that the following gives the same result:

mount -t sysfs /inventAnonExistentFilename.whatever targetDirectory/

adding -o loop also has no effect on the behavior.