chroot(8)						      System Manager's Manual							 chroot(8)

NAME

       chroot - Changes the root directory of a command

SYNOPSIS

       /usr/sbin/chroot directory command

DESCRIPTION

       Only  root  can	use  the chroot command.  The chroot command changes the root directory from / to the specified directory when the command
       executes. (The command specified includes both the command name as well as any arguments.) Consequently, the root of any path (as indicated
       by  the first / (slash) in the pathname) changes to directory and is always relative to the current root.  Even if the chroot command is in
       effect, directory is relative to the current root of the running process.

       Several programs may not operate properly after chroot executes.  You must ensure that all vital files are present in  the  new	root  file
       system and the relevant pathnames for the files map correctly in the new root file system.

       For  example,  the ls -l command fails to give user and group names if the new root file system does not have a copy of the /etc/passwd and
       /etc/group files.  If the /etc/passwd and /etc/group files in the new root file system represent different user and group names,  then  the
       output  from  the  ls  -l  command will be based on those names, not the ones for the system's own name database.  Utilities that depend on
       description files produced by the ctab command may also fail if the required description files are not present in the new root file system.

       The chroot program uses the execv() function to invoke the specified command.  As a consequence, the command  specified	must  be  an  exe-
       cutable	binary,  not  a shell script.  Further, if the program requires indirect loading (for example, due to unresolved symbols requiring
       use of a shared library), then /sbin/loader as well as any files it requires (for example, shared libraries) must be  present  in  the  new
       root file system in the appropriate locations.

EXAMPLES

       To run a subshell with another file system as the root, enter a command similar to the following.  Note in this example, the file system is
       on the /dev/disk/dsk13a device and is mounted to /mnt/dsk13a: chroot  /mnt/dsk13a  /sbin/sh The command shown in the previous example spec-
       ifies a change from the current root file system to the one mounted on /mnt/dsk13a while /sbin/sh (which itself is relative to the new root
       file system) executes.  When /bin/sh executes, the original root file system is inaccessible.  The file system mounted on /mnt/dsk13a  must
       contain	the  standard  directories  of a root file system. In particular, the shell looks for commands in /sbin, /bin, and /usr/bin (among
       others) on the new root file system.

       Running the /sbin/sh command creates a subshell that runs as a separate process from the original shell.  Press to exit	the  subshell  and
       return to the original shell.  This restores the environment of the original shell, including the meanings of the current directory (.) and
       the root directory (/).	To run a command in another root file system and save the output on the initial root file system, enter a  command
       similar to the following.  Note in this example, the file system is on the /dev/disk/dsk13a device and is mounted to /mnt/dsk13a:

       chroot  /mnt/dsk13a  /bin/cc  -E  /u/bob/prog.c	> prep.out

       The previous command runs the /bin/cc command with /mnt/dsk13a as the specified root file system.  It compiles the /mnt/dsk13a/u/bob/prog.c
       file, reads the #include files from the /mnt/dsk13a/usr/include directory, and puts the compiled text in the prep.out file on  the  initial
       root file system.  To create a file relative to the original root rather than the new one, use this syntax and enter:

       chroot  directory command > file

CAUTIONS

       If special files in the new root have different major and minor device numbers than the initial root directory, it is possible to overwrite
       the file system.

FILES

       Specifies the command path.

RELATED INFORMATION

       Commands:  cc(1), cpp(1), ls(1), sh(1)

       Functions:  chdir(2), chroot(2) exec(2) delim off

																	 chroot(8)