HIER(7)

NAME
hier - layout of file systems

DESCRIPTION
An outline of the file system hierarchy.

Naming is very important. The UNIX System relies on filename conventions for much of its power as a system. The following file system layout describes generally where things are and what they are, with references to other man pages for more detailed documentation.

Not all files will be in every system.

/   Root directory of the system.

/COPYRIGHT
    System copyright notice, most often put on CD-ROM distributions.

/[a-z]/
    User file systems.

/altroot/
    Alternate root file system, in case of disaster.

/bin/
    Utilities used in both single and multi-user environments.

/boot*
    Second-stage boot loader(s) for some platforms; see installboot(8).

/cdrom/
    Empty directory commonly used by system administrators as a temporary mount point for ISO-9660 file systems on CD (or DVD) media.

/dev/
    Block, character, and other special device files.

    MAKEDEV
        Script for creating device files; see makedev(8).
    console
        The computer's console device.
    drum
        The computer's swap space device; see drum(4).
    fd/ File descriptor files; see fd(4).
    klog
        Kernel logging device; see syslog(3).
    kmem
        Kernel virtual memory device; see mem(4).
    log UNIX domain datagram log socket; see syslogd(8).
    mem Kernel physical memory device; see mem(4).
    null
        The null device; see null(4).
    pts/
        Mount point for the pseudo-terminal device file system; see mount_ptyfs(8).
    stderr
    stdin
    stdout
        File descriptor files; see fd(4).
    tty Device pointing to each process's own controlling terminal; see tty(4).
    zero
        The zero device; see zero(4).

/etc/
    System configuration files and scripts.

    amd*
        Configuration files for amd(8).
    changelist
        Files backed up by the security script.
    crontab
        Schedule used by the cron(8) daemon.
    csh.cshrc
    csh.login
    csh.logout
        System-wide scripts for csh(1).
    daily
        Script run each day by cron(8).
    daily.conf
        Configuration file for daily; see daily.conf(5).
    defaults/
        Default configuration files read by various /etc/*.conf files.
    disktab
        Disk description file; see disktab(5).
    dm.conf
        Dungeon master configuration; see dm.conf(5).
    dumpdates
        Dump history; see dump(8).
    exports
        File system export information; see mountd(8).
    fstab
        File system mounting table; see fstab(5) and mount(8).
    ftpusers
        Users denied ftp(1) access; see ftpd(8).
    ftpwelcome
        ftp(1) initial message; see ftpd(8).
    gettytab
        Terminal configuration database; see gettytab(5).
    group
        Group permissions file; see group(5).
    hosts
        Host name database backup for named(8); see hosts(5).
    hosts.equiv
        Trusted machines with equivalent user IDs. (Obsolete.)
    hosts.lpd
        Trusted machines with printing privileges.
    inetd.conf
        Internet server configuration file; see inetd(8).
    kerberosV/
        Configuration files for Kerberos version V; see kerberos(8).
    localtime
        Local time zone; see ctime(3).
    login.conf
        Configuration of user classes and limits; see login.conf(5).
    mail/
        Configuration files for sendmail(1).

        aliases*
            Username alias files.
        sendmail.*
            sendmail(1) configuration information.
    mail.rc
        System-wide initialization script for mail(1).
    man.conf
        Configuration file for man(1); see man.conf(5).
    master.passwd
        Main password file, readable only by root; see passwd(5).
    mk.conf
        Optional file containing make(1) variables, used to configure pkgsrc and the system sources.
    monthly
        Script run each month by cron(8).
    monthly.conf
        Configuration file for monthly; see monthly.conf(5).
    motd
        System message of the day.
    mtree/
        mtree(8) configuration files.
    named.*
    namedb/
        named(8) configuration files and databases.
    netgroup
        Network groups; see netgroup(5).
    networks
        Network name database; see networks(5).
    openssl/
        OpenSSL TLS trust anchors, configuration file, private keys, and more. Returned by X509_get_default_cert_area(3).
        certs/
            Hashed directory of trust anchors for TLS certificate validation. Managed by certctl(8) according to certs.conf. See openssl_rehash(1). Returned by X509_get_default_cert_dir(3).
        certs/ca-certificates.crt
            Bundle of TLS anchors in PEM format formed by concatenation of PEM-format certificates. Managed by certctl(8) according to certs.conf.
        certs.conf
            Configuration file for certctl(8).
        misc/
            Miscellaneous OpenSSL scripts. Unused in NetBSD base.
        openssl.cnf
            Optional default OpenSSL configuration file. See openssl_config(5). Returned by CONF_get1_default_config_file(3).
        private/
            Private key area. Read/write/execute permitted only by root. Unused in NetBSD base. Returned by X509_get_default_private_dir(3).
    passwd
        World readable password file generated from master.passwd; see passwd(5), pwd_mkdb(8).
    phones
        Remote host telephone number data base; see phones(5).
    printcap
        Printer configuration for lpr(1); see printcap(5).
    profile
        System-wide scripts for sh(1).
    protocols
        Protocol name database; see protocols(5).
    pwd.db
        Database form of passwd file; see pwd_mkdb(8).
    rc  Master system startup script invoked by init(8); see rc(8).
    rc.conf
        Configuration file for system startup and shutdown scripts; see rc.conf(5).
    rc.d/
        Directory containing per-subsystem startup and shutdown scripts; see rc(8).
    rc.local
        Locally editable system startup script.
    rc.shutdown
        Master system shutdown script invoked by shutdown(8); see rc(8).
    remote
        Remote host description file; see remote(5).
    security
        Daily (in)security script run by cron(8).
    security.conf
        Configuration file for security; see security.conf(5).
    services
        Service name data base; see services(5).
    shells
        List of permitted shells; see shells(5).
    skel/
        Sample initialization files for new user accounts.
    sliphome/
        SLIP login/logout scripts; see sliplogin(8).
    spwd.db
        Database form of master.passwd file; see pwd_mkdb(8).
    syslog.conf
        syslogd(8) Configuration file; see syslog.conf(5).
    ttyaction
        Login hooks for specific ttys, typically used to chown console devices. See ttyaction(5).
    ttys
        Terminal initialization information; see ttys(5).
    weekly
        Script run each week by cron(8).
    weekly.conf
        Configuration file for weekly; see weekly.conf(5).

/home/
    Default location for user home directories.

/kern/
    Mount point for the kern file system; see mount_kernfs(8).

/lib/
    Dynamic linked libraries used by dynamically linked programs that cannot rely upon /usr/lib/ being available, such as those in /bin/ and /sbin/.

/libdata/
    Non-executable files (such as device firmware) required at boot time, when /usr/libdata may not be available.

/libexec/
    System utilities (such as the dynamic linker) required by programs and libraries that cannot rely upon /usr/libexec/ being available.

/mnt/
    Empty directory commonly used by system administrators as a temporary mount point.

/net/
    automounted NFS shares; see auto_master(5)

/netbsd
    Kernel executable image (the operating system loaded into memory at boot time).

/proc/
    Mount point for the process file system; see mount_procfs(8).

/rescue/
    Statically linked rescue tools, for use in system recovery.

/root/
    Home directory for the super-user.

    .cshrc
        Super-user start-up file for csh(1).
    .login
        super-user start-up file for csh(1).
    .profile
        super-user start-up file for sh(1).
    .rhosts
        Super-user id mapping between machines. (Obsolete.)

/sbin/
    System programs and administration utilities used in both single-user and multi-user environments.

/stand/
    Programs used in a standalone environment, that is, things that run on bare hardware without a kernel. Currently kernel modules are also placed here (except when building with KERNEL_DIR, see mk.conf(5)), although this remains somewhat controversial and they may yet get moved.

/tmp/
    Temporary files. The contents of /tmp are usually not preserved across a system reboot.

/usr/
    Contains the majority of the system utilities and files.

    X11R7/
        X11 files (for X11 revision 7).

        bin/
            X11 binaries.
        include/
            X11 include files.
        lib/
            X11 libraries.

    bin/
        Common utilities, programming tools, and applications.
    games/
        The important stuff.
    include/
        Standard C (and extension) include files.

        arpa/
            Include files for Internet service protocols.
        atf/
            Include files for the Automated Testing Framework; see atf(7).
        g++/
            Include files for the GNU C++ compiler.
        machine/
            Machine specific include files.
        net/
            Miscellaneous network include files.
        netatalk/
            C include files for AppleTalk protocols see atalk(4).
        netinet/
            Include files for Internet standard protocols; see inet(4).
        netinet6/
            Include files for Internet protocol version 6; see inet6(4).
        netipsec/
            Include files for secret key management, used for security protocols; see ipsec(4).
        nfs/
            C include files for NFS (Network File System).
        protocols/
            C include files for Berkeley service protocols.
        sys/
            ``System-level'' C include files.
        ufs/
            C include files for several mutually related file systems. (The `u' was originally for UNIX.)

    lib/
        Archive, profiled, position independent archive, and shared libraries.

        lua/
            5.3/
                Lua 5.3 modules.

    libdata/
        Miscellaneous utility data files.
    libexec/
        System daemons & system utilities (executed by other programs).

    mdec/
        Boot blocks, etc.
    obj/
        Architecture-specific target tree produced by building the /usr/src tree; often a symbolic link or mounted file system.
    pkg/
        Installed third-party software packages.

        bin/
            Package binaries.
        etc/
            Package configuration files.
        include/
            Package include files.
        lib/
            Package libraries.
        libdata/
            Package data files.
        libexec/
            Package daemons.
        sbin/
            Package system utilities.

    pkgsrc/
        Build descriptions (packaging) for the NetBSD package system.

        distfiles/
            Downloaded upstream source archives.
        packages/
            Compiled binary packages.

        There are also several other subdirectories which contain packages of a certain category, e.g., archivers, graphics, ...

    sbin/
        System daemons and system utilities (normally executed by the super-user).
    share/
        Architecture-independent files, mostly text.

        calendar/
            A variety of calendar files; see calendar(1).
        certs/mozilla/
            X.509 certificates from Mozilla's curated set of certificate authorities (CAs), certdata.txt, in PEM format. See for details. Used by certctl(8) to populate OpenSSL trust anchors at /etc/openssl/certs.
            all/
                Certificates of all CAs in Mozilla certdata.txt, for all purposes, including CAs Mozilla may no longer trust.
            code/
                Certificates of CAs trusted by Mozilla for code-signing.
            email/
                Certificates of CAs trusted by Mozilla for email with S/MIME.
            code/
                Certificates of CAs trusted by Mozilla for TLS server authentication.
        dict/
            Word lists; see look(1) and spell(1).

            words
                Common words.
            web2
                Words from Webster's Second International Dictionary.
            papers/
                Reference databases; see refer(1).
            special/
                Custom word lists; see spell(1).

        doc/
            Miscellaneous documentation.
        games/
            Data files used by various games.
        i18n/
            internationalization databases; see iconv(3).
        locale/
            Locale databases and gettext message catalogs; see setlocale(3) and gettext(3).
        man/
            Manual pages.
        me/ Macros for use with the me(7) roff macro package.
        misc/
            Miscellaneous system-wide text files.

            terminfo
                Terminal characteristics database; see terminfo(5).
            terminfo.cdb
                database form of terminfo file; see tic(1).

        mk/ Include files for make(1).
        ms/ Macros for use with the ms(7) roff macro package.
        nls/
            Message catalogs; see catgets(3).
        tmac/
            Text processing macros; see nroff(1) and troff(1).
        zoneinfo/
            Time zone database; see tzfile(5).
    tests/
        Test programs; see tests(7) for information on how to run them.

/usr/src/
    NetBSD and local source files.

    bin/
        Source for utilities/files in /bin.
    common/
        Sources shared between kernel and userland.
    crypto/
        Cryptographic source, which may have import or export restrictions.
    dist/
        Third-party ‘virgin’ source code, referenced by other parts of the source tree. (Deprecated; use external/ instead.)
    distrib/
        Tools and data files for making NetBSD releases and distributions.
    doc/
        Documentation about the source tree (i.e., about the tree, not about how to use the software in the tree.)
    etc/
        Source (usually example files) for files in /etc.
    external/
        Source for programs from external third parties (where NetBSD is the not the primary maintainer), grouped by license, and then products per license.

        apache2/
            Apache 2.0 license.
        bsd/
            BSD (or equivalent) licensed software, possibly with the “advertising clause”.
        broadcom/
            Broadcom firmware license.
        cddl/
            Common Development and Distribution License (the Sun license which is based on the Mozilla Public License version 1.1).
        gpl2/
            GNU Public License, version 2 (or earlier).
        gpl3/
            GNU Public License, version 3.
        historical/
            Lucent's old license.
        ibm-public/
            IBM's public license.
        intel-fw-eula/
            Intel firmware license with redistribution restricted to OEM.
        intel-fw-public/
            Intel firmware license permitting redistribution with terms similar to BSD licensed software.
        intel-public/
            Intel license permitting redistribution with terms similar to BSD licensed software.
        lgpl3/
            GNU lesser general public license, version 3.
        mit/
            MIT (X11) style license.
        mpl/
            Mozilla Public License.
        zlib/
            BSD-like zlib license.

    games/
        Source for utilities/files in /usr/games.
    include/
        Source for files in /usr/include.
    lib/
        Source for libraries in /usr/lib.
    libexec/
        Source for utilities/files in /usr/libexec.
    regress/
        Various legacy regression tests.
    rescue/
        Source/makefiles for /rescue.
    sbin/
        Source for utilities/files in /sbin.
    share/
        Source for files in /usr/share.

        doc/

            papers/
                Source for various historical technical papers (many from Berkeley).
            psd/
                Source for Programmer's Supplementary Documents.
            smm/
                Source for System Manager's Manual.
            usd/
                Source for User's Supplementary Documents.
    sys/
        Kernel source files.

        arch/
            Architecture-specific support.

            acorn32/
                Acorn RiscPC/A7000 and VLSI RC7500.
            algor/
                Algorithmics Ltd. MIPS evaluations boards.
            alpha/
                Digital/Compaq Alpha.
            amd64/
                Computers with x86_64 capable CPUs.
            amiga/
                Commodore Amiga and MacroSystem DraCo.
            amigappc/
                PowerPC based Amiga boards.
            arc/
                MIPS-based machines following the Advanced RISC Computing spec.
            arm/
                ARM processor general support.
            atari/
                Atari TT030, Falcon and Hades.
            bebox/
                Be Inc. BeBox.
            cats/
                Chalice Technology's CATS and Intel's EBSA-285 evaluation boards.
            cesfic/
                CES FIC8234 VME processor board.
            cobalt/
                Cobalt Networks' MIPS-based Microserver.
            dreamcast/
                Sega Dreamcast game console.
            emips/
                Machines based on Extensible MIPS.
            evbarm/
                ARM based evaluation boards.
            evbmips/
                MIPS based evaluation boards.
            evbppc/
                PowerPC based evaluation boards and appliances.
            evbsh3/
                SH3/SH4 based evaluation boards.
            ews4800mips/
                NEC's MIPS based EWS4800 workstations.
            hp300/
                Hewlett-Packard 9000/300 and 400 680x0-based workstations.
            hppa/
                Hewlett-Packard 9000/700 and 9000/800 HPPA based workstations.
            hpcarm/
                StrongARM based WinCE PDA machines.
            hpcmips/
                MIPS based WinCE PDA machines.
            hpcsh/
                Hitachi SH3/4 based WinCE PDA machines.
            hppa/
                HPPA processor general support.
            i386/
                32-bit 80x86-based IBM PCs and clones.
            ibmnws/
                IBM Network Station 1000.
            iyonix/
                Castle Technology's Iyonix ARM based PCs.
            luna68k/
                Omron Tateishi Electric's 680x0-based LUNA workstations.
            m68k/
                680x0 processor general support.
            mac68k/
                Apple Macintosh with 68k CPU.
            macppc/
                Apple Power Macintosh and clones.
            mips/
                MIPS processor general support.
            mipsco/
                MIPS Computer Systems Inc. family of workstations and servers.
            mmeye/
                Brains Inc. SH3 based mmEye multimedia server.
            mvme68k/
                Motorola MVME 680x0-based SBCs.
            mvmeppc/
                Motorola PowerPC VME SBCs.
            netwinder/
                StrongARM based NetWinder machines.
            news68k/
                Sony's 680x0-based NEWS workstations.
            newsmips/
                Sony's MIPS-based NEWS workstations.
            next68k/
                NeXT 68k "black" hardware.
            ofppc/
                Open Firmware PowerPC workstations.
            playstation2/
                SONY PlayStation 2.
            pmax/
                Digital MIPS-based DECstations and DECsystems.
            powerpc/
                PowerPC processor general support.
            prep/
                PReP (PowerPC Reference Platform) and CHRP (Common Hardware Reference Platform) machines.
            sandpoint/
                Motorola Sandpoint reference platform.
            sbmips/
                Broadcom/SiByte evaluation boards.
            sgimips/
                Silicon Graphics' MIPS-based workstations.
            sh3/
                SH3/SH4 processor general support.
            shark/
                Digital DNARD ("Shark").
            sparc/
                Sun Microsystems SPARC (32-bit) and UltraSPARC (in 32-bit mode).
            sparc64/
                Sun Microsystems UltraSPARC (in native 64-bit mode).
            sun2/
                Sun Microsystems 68010-based Sun 2 architecture.
            sun3/
                Sun Microsystems 68020/68030-based Sun 3/3x architecture.
            sun68k/
                680x0-based Sun architecture general support.
            vax/
                Digital VAX.
            x68k/
                Sharp X680x0 680x0-based workstations.
            x86/
                General support for PC/AT compatibles with ia32 or x86_64 CPUs.
            xen/
                The Xen virtual machine monitor.
            zaurus/
                Sharp C3x00 Arm based PDA.

        compat/
            Kernel compatibility modules directory.

            common/
                Common compatibility routines, old 4BSD and NetBSD routines.
            freebsd/
                Support for FreeBSD binaries; see compat_freebsd(8).
            hpux/
                Support for 68000 HP-UX binaries.
            linux/
                Support for Linux binaries; see compat_linux(8).
            m68k4k/
                Support for 4KB page 68000 binaries.
            netbsd32/
                Support for NetBSD 32-bit binaries on 64 bit platforms with compatible CPU families.
            ossaudio/
                Support for OSS audio.
            sunos/
                Support for SunOS 4.x binaries; see compat_sunos(8).
            ultrix/
                Support for ULTRIX binaries.
            vax1k/
                Support for older VAX binaries that started on a 1 KB boundary.

        conf/
            Architecture independent configuration directory.
        crypto/
            Cryptographic kernel source, which may have import or export restrictions.
        ddb/
            In-kernel debugger.
        dev/
            Architecture independent device support.
        fs/ File systems. See also ufs/ and miscfs/.
            adosfs/
                AmigaDOS file-system support; see mount_ados(8).
            cd9660/
                Support for the ISO-9660 file system; see mount_cd9660(8).
            filecorefs/
                Support for the Acorn RISC OS filecore file system; see mount_filecore(8).
            msdosfs/
                MS-DOS file system; see mount_msdos(8).
            ntfs/
                NTFS file system support; see mount_ntfs(8).
            ptyfs/
                Pseudo-terminal device file system; see mount_ptyfs(8).
            union/
                Union file system; see mount_union(8).
        gdbscripts/
            Support for accessing kernel structures from within the debugger gdb(1).

        kern/
            Primary kernel source code.
        lib/
            Libraries supporting the kernel.

            libkern/
                C library routines used in the kernel.
            libsa/
                Machine-independent standalone library, used by boot loaders.
            libz/
                Compression library.

        miscfs/
            More file systems.

            deadfs/
                Kernel only dead file system.
            fdesc/
                File descriptor file system; see mount_fdesc(8).
            fifofs/
                POSIX FIFO (named pipe) support.
            genfs/
                Generic file system code that supports other file systems.
            kernfs/
                Kernel namespace file system; see mount_kernfs(8).
            nullfs/
                Loop back file system; see mount_null(8).
            overlay/
                Overlay file system; see mount_overlay(8).
            procfs/
                Process file system; see mount_procfs(8).
            specfs/
                Support for block and character special files.
            syncfs/
                Kernel trickle sync algorithm.
            umapfs/
                User and group re-mapping file system; see mount_umap(8).

        net/
            Miscellaneous networking support.
        netatalk/
            AppleTalk networking support.
        netinet/
            IP networking support.
        netinet6/
            IPv6 networking support.
        netipsec/
            Key database for IPsec networking support.
        nfs/
            NFS (network file system) support, both client and server.
        stand/
            Kernel standalone support.
        sys/
            Kernel (and system) include files.
        ufs/
            Still more file systems.

            chfs/
                A FFS-based file system for use on raw flash.
            ext2fs/
                The Linux ext2 file system.
            ffs/
                The Berkeley Fast File System.
            lfs/
                The Berkeley log-structured file system.
            mfs/
                The in-memory file system.
            ufs/
                Shared UNIX file system support.
        uvm/
            UVM virtual memory system.
    tests/
        Source for test programs in /usr/tests.
    usr.bin/
        Source for utilities/files in /usr/bin.
    usr.sbin/
        Source for utilities/files in /usr/sbin.

/var/
    Multi-purpose log, temporary, transient, and spool files.

    account/
        System accounting files.

        acct
            Execution accounting file; see acct(5).

    at/ Timed command scheduling files; see at(1).
    backups/
        Miscellaneous backup files, largely of files found in /etc.
    chroot/
        Home directories of applications which are run in a chroot(8) “cage”.
    crash/
        System (kernel) crash dumps; see savecore(8).
    cron/
        Scheduled commands configuration files; see cron(8) and crontab(5).
    db/ Miscellaneous automatically generated system-specific database files, and persistent files used in the maintenance of third party software.
    games/
        Miscellaneous game status, log, and high score files.
    heimdal/
        Kerberos 5 KDC database; see kdc(8).
    log/
        Miscellaneous system log files.

        amd.*
            amd(8) logs.
        daily.out
            Output of the last run of the /etc/daily script.
        ftp.*
            ftp(1) logs.
        kerberos.*
            kerberos(8) logs.
        lastlog
            System last-time-logged-in database; see utmp(5).
        lpd-errs.*
            Printer daemon error logs; see lpd(8).
        maillog.*
            sendmail(1) and postfix(1) (and other mail-related) log files.
        messages.*
            General system information log.
        monthly.out
            Output of the last run of the /etc/monthly script.
        secure
            Sensitive security information log.
        sendmail.st
            sendmail(1) statistics.
        timed.*
            timed(8) logs.
        weekly.out
            Output of the last run of the /etc/weekly script.
        wtmp
            Login and logout log; see utmp(5).
        wtmpx
            Another login and logout log; see utmpx(5).

    mail/
        User e-mail inboxes.
    msgs/
        System messages; see msgs(1).
    preserve/
        Temporary home of files preserved after an accidental death of ex(1) or vi(1).
    quotas/
        File system quota information. (Legacy.)
    run/
        System information files, rebuilt after each reboot.

        dmesg.boot
            A dump from dmesg(8) taken at boot time.
        utmp
            Database of currently logged in users; see utmp(5).
        utmpx
            Another database of currently logged in users; see utmpx(5).

    rwho/
        Rwho data files; see rwhod(8), rwho(1), and ruptime(1).

    shm/
        Used as backing store for POSIX shared memory; see shm_open(3).

    spool/
        Miscellaneous printer and mail system spooling directories.

        ftp/
            Commonly “~ftp”, the anonymous ftp root directory; see ftpd(8).
        mqueue/
            Sendmail mail queue; see sendmail(1).
        news/
            Network news archival and spooling directories.
        output/
            Printer spooling directories.
        postfix/
            Postfix mail queue; see postfix(1).

    tmp/
        Temporary files that are not discarded between system reboots.

        vi.recover/
            Recovery directory for new (current) vi(1).

    yp/ Databases and configuration for the NIS (YP) system; see nis(8).

SEE ALSO
apropos(1), ls(1), whatis(1), whereis(1), which(1), paths(3)

HISTORY
A hier manual page appeared in AT&T UNIX.