%general-entities; ]> Creating Essential Files A proper Linux system maintains a list of the mounted file systems in the file /etc/mtab. Normally, this file would be created when we mount a new file system. Since we will not be mounting any file systems inside our chroot environment, create an empty file for utilities that expect the presence of /etc/mtab: touch ${LFS}/etc/mtab In order for user root to be able to login and for the name root to be recognized, there must be relevant entries in the /etc/passwd and /etc/group files. Create the /etc/passwd file by running the following command: cat > %{LFS}/etc/passwd << "EOF" root:x:0:0:root:/root:/bin/bash EOF The actual password for root (the x used here is just a placeholder) will be set later. Create the /etc/group file by running the following command: cat > ${LFS}/etc/group << "EOF" root:x:0: bin:x:1: sys:x:2: kmem:x:3: tty:x:4: tape:x:5: daemon:x:6: floppy:x:7: disk:x:8: lp:x:9: dialout:x:10: audio:x:11: video:x:12: utmp:x:13: usb:x:14: cdrom:x:15: EOF The created groups are not part of any standard—they are groups decided on in part by the requirements of the Udev configuration in this chapter, and in part by common convention employed by a number of existing Linux distributions. The Linux Standard Base (LSB, available at ) recommends only that, besides the group root with a Group ID (GID) of 0, a group bin with a GID of 1 be present. All other group names and GIDs can be chosen freely by the system administrator since well-written programs do not depend on GID numbers, but rather use the group's name. The login, agetty, and init programs (and others) use a number of log files to record information such as who was logged into the system and when. However, these programs will not write to the log files if they do not already exist. Initialize the log files and give them proper permissions: touch ${LFS}/var/run/utmp ${LFS}/var/log/{btmp,lastlog,wtmp} chgrp -v utmp ${LFS}/var/run/utmp ${LFS}/var/log/lastlog chmod -v 664 ${LFS}/var/run/utmp ${LFS}/var/log/lastlog The /var/run/utmp file records the users that are currently logged in. The /var/log/wtmp file records all logins and logouts. The /var/log/lastlog file records when each user last logged in. The /var/log/btmp file records the bad login attempts.