How-to: Layout of the macOS Filesystem

A historical sketch of the filesystem hierarchy. (The modern macOS filesystem adds many other folders to this basic structure).

     /             root directory of the filesystem

     /bin/         user utilities fundamental to both single-user and multi-user environments

     /dev/         block and character device files

                   fd/  file descriptor files; see fd(4)

     /etc/         system configuration files and scripts

     /mach_kernel  kernel executable (the operating system loaded into memory at boot time).

     /sbin/        system programs and administration utilities fundamental to both single-
                   user and multi-user environments

     /tmp/         temporary files

     /usr/         contains the majority of user utilities and applications

                   bin/      common utilities, programming tools, and applications
                   include/  standard C include files

                             arpa/       C include files for Internet service protocols
                             hfs/        C include files for HFS
                             machine/    machine specific C include files
                             net/        misc network C include files
                             netinet/    C include files for Internet standard protocols; see
                             nfs/        C include files for NFS (Network File System)
                             objc/       C include files for Objective-C
                             protocols/  C include files for Berkeley service protocols
                             sys/        system C include files (kernel data structures)
                             ufs/        C include files for UFS

                   lib/      archive libraries
                   libexec/  system daemons & system utilities (executed by other programs)
                   local/    executables, libraries, etc. not included by the basic operating
                   sbin/     system daemons & system utilities (executed by users)
                   share/    architecture-independent data files

                             calendar/  a variety of pre-fab calendar files; see calendar
                             dict/      word lists; see look(1)

                                        web2        words from Webster's 2nd International
                                        words       common words

                             man/       manual pages
                             misc/      misc system-wide ascii text files
                             mk/        templates for make; see make(1)
                             skel/      example . (dot) files for new accounts
                             tabset/    tab description files for a variety of terminals; used
                                        in the termcap file; see termcap(5)
                             zoneinfo/  timezone configuration information; see tzfile(5)

     /var/         multi-purpose log, temporary, transient, and spool files

                   at/        timed command scheduling files; see at(1)
                   backups/   misc. backup files
                   db/        misc. automatically generated system-specific database files
                   log/       misc. system log files

                   mail/      user mailbox files
                   run/       system information files describing various info about system
                              since it was booted

                              utmpx       database of current users; see utmpx(5)

                   rwho/      rwho data files; see rwhod(8), rwho(1), and ruptime(1)
                   spool/     misc. printer and mail system spooling directories

                              mqueue/     undelivered mail queue; see sendmail(8)

                   tmp/       temporary files that are kept between system reboots
                   folders/   per-user temporary files and caches

Related macOS commands

macOS How To
ls, apropos(1), whatis, whereis(1), finger(1), which, find, grep, fsck

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