StartupShell(8) StartupShell(8)NAME StartupShell - interprets command lines, such as those used to boot A/UX and check file systems, within the A/UX Startup application DESCRIPTION The A/UX Startup application includes StartupShell, which interprets command lines that can give you access to files within an A/UX file system. It also offers menus that help establish how A/UX is launched (booted). The shell portion of A/UX Startup is referred to as StartupShell. StartupShell faithfully reproduces much of the operating environment of a shell application. (The coverage of this manual page is not limited to the StartupShell portion of A/UX Startup.) A dialog box available from the Preferences menu lets you establish how A/UX is booted. For example, you can determine what programs will be called to check and repair file systems. Using the command-line interface, you can devise a special command line that boots A/UX in some particular way, without establishing it as your preferred boot method. For example, you can supply the -S option to the launch command to boot A/UX into single-user mode, regardless of what is specified in /etc/inittab as the initial system startup state. When A/UX Startup is first launched, A/UX is not yet running. However, you can still have access to files in A/UX file systems. If you wish, A/UX Startup lets you password-protect all its functionality, except for booting A/UX. Other options for securing A/UX Startup can be established through the auxstartuprc control file as described in auxstartuprc(4). For example, the full use of the functions of A/UX Startup can be limited to specific accounts. To provide added security, you can establish password checking by clicking the appropriate checkbox in the General Preferences dialog box of A/UX Startup. Password checking requires a user to enter the root account password before they can gain comprehensive access to the functions of A/UX Startup, including the command-line interface. If the ``Automatically Boot at Startup'' checkbox is not selected, then each time a user launches A/UX Startup to boot A/UX they are taken directly to the login dialog box. This dialog box also contains a button that lets users start A/UX without having to enter a properly qualified login name and password. If the ``Automatically Boot at Startup'' checkbox is selected, then launching A/UX Startup automatically starts A/UX, and no login dialog box appears before the boot progress bar. In such a case, if a user cancels the boot March 1993 1
StartupShell(8) StartupShell(8)process, the login dialog box appears along with a button to shut the system down, and a button to restart the A/UX boot process. Other accounts or groups of accounts can be authorized for comprehensive access to A/UX Startup by placing a login name, user ID, group ID, or any combination of these into the first three fields of /etc/auxstartuprc, as described in auxstartuprc(4). Values in the remaining fields in /etc/auxstartuprc can also affect the operation of A/UX Startup. For example, a value in the nofinder-flag field prevents users from being able to access the Finder once A/UX Startup is running. Your work sessions in A/UX are often affected by the presence of a /etc/auxstartuprc file. When it is present, the Finder will not display an icon for the Macintosh volume that resides on the same disk as the root file system unless you logged in as root. If you enable password checking in A/UX Startup, A/UX Startup ensures that the auxstartuprc file exists, creating it as an empty file if necessary. If you disable password checking, A/UX Startup attempts to delete the file, but only if it is empty. So an undeleted auxstartuprc file continues to affect A/UX work sessions even though password checking in A/UX Startup is switched off. The A/UX work sessions of each user are likely to be affected when an /etc/auxstartuprc file is present because the Finder in A/UX does not display the desktop icon for the Macintosh volume (normally called MacPartition) on the root disk device. This is an added security measure that prevents normal users from being able to manipulate any of the files on this Macintosh volume. (Users should not store their A/UX work on this Macintosh volume, which primarily exists for the purpose of booting A/UX). An exception is made if you begin your A/UX work session by logging in as root. Although it can give you access to many functions, A/UX Startup is normally used just to boot A/UX whenever its icon is ``opened'' from the Macintosh Finder. To boot A/UX whenever the computer system is started, A/UX users normally set the Macintosh Finder to automatically launch A/UX Startup through the Set Startup command in the Finder's Special menu. This procedure is relevant if you upgraded to A/UX 3.0 without switching to System 7.0 for the MacPartition. This procedure is also relevant when system software prior to System 7.0 runs on the disk designated as the startup disk when the computer is first started. 2 March 1993
StartupShell(8) StartupShell(8)If you followed a complete installation procedure, the MacPartition is loaded with System 7.0. When System 7.0 runs upon system startup, you use a different method to cause A/UX Startup to run automatically. You place an alias of the A/UX Startup application in the Startup Items folder that is inside the System Folder of the startup disk. (You may want to use the Startup Disk control panel to see what disk is currently designated as the startup disk.) A/UX Startup displays a progress bar for the booting process, indicating the current status of the A/UX startup sequence. It also displays a Cancel button until the boot process is beyond the point of no return. If you click the Cancel button in time to stop the booting of A/UX, A/UX Startup is left running under the Macintosh Operating System. The commands that StartupShell allows you to run are often faithful reproductions of their A/UX counterparts. Most of them are located in a MacPartition folder called bin. These files can only be opened by the A/UX Startup application. A list of these executable files is given in ``Program Files Executable as Commands'' later in the ``Description'' section. You can use the A/UX Startup menus to establish boot preferences and invoke selected command functions without doing any typing. These menus are described in detail in ``Menu Items'' later in this section. The command-line operating environment is also discussed later in this section. The AutoRecovery and AutoLaunch menu items in the Execute menu are configurable commands. Using them is equivalent to running the command strings stored in the command-aliasing variables autorecovery and autolaunch. The initial value of autolaunch is the command launch. The initial value of autorecovery is the command fsck -y -p /dev/default. The scope of the Boot menu item in the Execute menu is very broad because the Boot menu item invokes the command strings associated with both autorecovery and autolaunch. The AutoRecovery menu item invokes only the command string associated with autorecovery. The AutoRecovery provision is needed to ensure the validity of file systems before A/UX makes them available for updates. Menu Items The A/UX Startup application has two basic modes of operation. When it is starting A/UX, it disables its menus March 1993 3
StartupShell(8) StartupShell(8)and displays a progress bar and Cancel button. When it is not attempting to start A/UX, A/UX Startup displays the Apple menu and menus titled File, Edit, Execute, and Preferences in the menu bar at the top of the screen. Each menu contains items that perform various A/UX Startup functions. Apple menu. The Apple menu contains the customary items, such as a Chooser item. Several of its items can be useful for working with A/UX Startup. (The configuration of this menu depends upon the configuration of particular folders in the Macintosh partition of the startup disk; A/UX system folders can't have an effect on this menu because A/UX Startup does not run under the control of A/UX.) About A/UX Startup... Displays a window with some information about A/UX Startup. Help Displays a help message that lists the commands for which help is available. If necessary, a shell window is opened for the purpose of displaying this text and for accepting any command lines you wish to enter, such as help boot. File menu. The items in the File menu let you close the active window and quit A/UX Startup. Close Closes the currently active window. (The shell window cannot be closed.) Quit Quits A/UX Startup (same as the exit command). This menu item is dimmed if password checking is selected. Edit menu. The Edit menu displays the menu items Undo, Cut, Copy, Paste, and Clear. Except for Copy and Paste, these menu items are for use only with desk accessories. Execute menu. The items in the Execute menu let you run previously stored command strings. This menu contains the following items: Boot Executes the command strings assigned to the variables autorecovery and autolaunch (same as the boot command). AutoRecovery Executes the command string that has been assigned to the variable autorecovery (identical to the autorecovery command with no arguments). AutoLaunch 4 March 1993
StartupShell(8) StartupShell(8)Executes the command string that has been assigned to autolaunch (same as the autolaunch command with no arguments, except that the progress bar dialog box is displayed). Kill Halts the currently running A/UX Startup application. COMMAND-PERIOD and COMMAND-K are keyboard shortcuts for this item. Restart Restarts the computer (same as the restart command). Shut Down Shuts the system down (same as the built-in shutdown command). Preferences menu. The Preferences menu contains two menu items, Booting and General. Booting... Presents a dialog box that allows you to set various startup parameters associated with the boot command (and the Boot menu item in the Execute menu). Usually these preference values are stored in the Macintosh resource file for A/UX Startup so that they are persistent settings associated with a particular copy of A/UX Startup. Two dialog box items are checkboxes that can be toggled on and off: ⊕ Eject disks on Launch ⊕ Automatically Boot at startup If the ``Eject disks on Launch'' checkbox is selected, all ejectable media is automatically ejected at the time the A/UX kernel is launched. If the ``Automatically Boot at startup'' checkbox is selected, the shell automatically runs the boot command upon launching A/UX Startup, causing A/UX Startup to function as its namesake implies. To associate AutoRecovery functions to the AutoRecovery menu item, the Booting dialog box provides two radio buttons for checking the root file system or performing a custom command. For the last option, performing a custom command, a text box labeled ``Command'' allows you to enter your own AutoRecovery command. For example, you can choose to run fsck with your own set of command options, rather than using the default form of the command March 1993 5
StartupShell(8) StartupShell(8)available through the first radio button. Changing this value affects the value of the autorecovery variable. To support custom forms of booting commands, another text box labeled ``AutoLaunch Command'' is provided. If you leave this text box set to the default value, launch, the default boot options for launch are used. (See launch(8) for a description of the optional arguments.) Changing this value affects the value of the autolaunch variable. General... Presents a dialog box containing a checkbox for selecting or deselecting the password-checking feature and parity checking, as well as the following text boxes: ⊕ Root Directory ⊕ Home Directory The Root Directory text box displays the value of the built-in ROOT variable. You can change this value by editing the text in the text box. The Home Directory text box displays the value of the built-in HOME variable. You can change this value by editing the text in the text box. The value is stored in nonvolatile RAM (see nvram(7)). The A/UX Startup Shell Command Interface When you have suspended the booting of A/UX, you can either quit A/UX Startup in the usual fashion (as described in ``File Menu'' earlier in the ``Description'' section) or you can perform work using A/UX files on a floppy or hard disk that the Macintosh Operating System does not let you access otherwise. (The Macintosh OS recognizes only files and folders in Macintosh file systems.) Names of A/UX files can be given as arguments to a set of commands, such as ed and ls. Most of the commands that are available correspond to commands that run on A/UX. However, hard disks, partitions, file systems, and floppy disks may have to be specified differently, as described in ``Devices, Partitions, and Pathnames'' later in the ``Description'' section. The commands that you supply and the feedback that they provide appear in the command window that is automatically opened whenever A/UX Startup is not displaying a boot progress bar or a login dialog. 6 March 1993
StartupShell(8) StartupShell(8)The command interpreter (StartupShell) portion of A/UX Startup supports a command-based interface. For a shell program, the work of interpreting the commands you enter can be broken down into several steps: (1) prompting for and accepting lines of input; (2) processing the text of an input line, one part of which is expected to be the name of a command; and (3) locating and running the executable file containing the low-level instructions that give the command its functionality. Here is the default command prompt for StartupShell: startup# The executable files that the A/UX Startup shell can locate and run are those that reside in the bin folder located at the same level as the A/UX Startup application. You can establish other search paths by using the PATH variable (described in ``Command-Line Processing'' later in the ``Description'' section). However, you should not relocate the program files in the bin folder to any other folders. Several sections in the ``Description'' section offer detailed descriptions of how special characters entered on the command line can be used to trigger an execution mode, and the way that the A/UX Startup shell interprets them. Those sections include ``Command-Line Processing,'' ``Input,'' ``A/UX Startup Shell Variables,'' and ``Redirection.'' Basic Command-Line Requirements When one or more command arguments are being specified in addition to the command name, the white space (or blank) that separates them from the command name is required, as shown here: command-name [white-space command-argument]... Spaces and tabs are both referred to as white space, and one is as acceptable as the other when white space is required. White space is required between the command name and its sometimes optional command arguments. (Whether or not arguments are truly optional depends on the individual syntax requirements of each command, as described for the counterpart A/UX command in A/UX Command Reference.) Command-Line Processing The shell interprets each line of input as a single command. The first word in the command line is interpreted as the name of the command to be executed. March 1993 7
StartupShell(8) StartupShell(8)If a command name matches one of the special commands built into the shell, it is executed in StartupShell. (See ``Built-in Commands'' later in the ``Description'' section.) If the command name does not match a special command, a search for a program of the same name is conducted in the search paths stored in the PATH variable. You can define multiple search paths within the PATH variable by separating them with a vertical bar (|). This is the default search path: (mac):|(mac):bin: This search path specifies as search folders the folder in which A/UX Startup is located and, nested inside it, the bin folder, in that order. If you enter a command that includes a pathname, as signified by a leading slash (/) or left parenthesis (( ), the search paths in PATH are not used. Otherwise, each folder in the search path is searched for an executable file with the same name as the command given. The current ``environment'' (as described in environ(5)) is also passed to each program that you run. The environment consists of a list of variable names and variable values. The shell maintains the environment in several ways. On invocation, the shell reads the environment from a Macintosh resource. Using the built-in commands, you can modify the values of any of these variables or create new variables. Unless you use export to export those new variables and their latest values, neither their names nor their current values are placed in the environment and passed to commands. Once a variable has been placed in the environment, you can use the unexport or unset command to remove it. The environment used by an running program is thus composed of any unmodified name-value pairs initially established by the shell, minus any pairs removed by unexport and unset, plus any new assignments (or reassignments) that have been added through export commands. The command name is passed to the a program that you requested to run It is passed as the first element of the argument array (at the array index of 0). Most of the words following the first word in the command line are also passed to the program that you requested to run. The exceptions are words in positions that are subject to special interpretation because of nearby special characters. (See the next section, ``Input.'') 8 March 1993
StartupShell(8) StartupShell(8)Input A subset of the ordinary A/UX terminal interface is supported: specifically, the erase, kill, end-of-file, and end-of-line control characters; input flags for remapping characters; output flags not associated with delays; and local flags not associated with control characters. The control flags are not supported. Do not change the end-of- line character. The following characters have a special meaning to the shell and help delimit words: < > = newline space tab To suppress special interpretation of any of these characters, precede them with a backslash (\). This process is also called ``escaping'' the characters, and the backslash is called an escape character when used for this purpose. A newline preceded by a backslash is treated the same as a space character. All special characters enclosed by single quotation marks, except another single quotation mark, are treated as if each were preceded by a backslash. Most special characters enclosed within double quotation marks ("") are also treated as if they were preceded by a backslash. The exceptions are the backslash (\) and dollar sign ($), which are still treated as special characters. In accordance with the dollar sign being an exception, text enclosed within double quotation marks that contains a variable reference is processed so that the variable is replaced with its present value. However, a variable reference enclosed within single quotation marks is not replaced with the present value of the variables. Each line of input is considered to be a single command. A command is broken into words at white space except when the white space is enclosed in quotation marks or when white space characters are preceded by backslashes. A backslash (\) in the first word of a command disables automatic substitution for that command. The A/UX Startup shell prompts the user with the value of the PS1 variable before reading a command. A/UX Startup Shell Variables The shell allows you to create and remove variables that can be used to store values, such as preference settings. The name of a variable must be a sequence of letters, digits, or underscores, beginning with a letter or underscore. The only exception to these naming requirements is the variable named ?, which the shell updates after each command you run. March 1993 9
StartupShell(8) StartupShell(8)By referencing this variable ($?), you can inspect the exit status of the command that was run most recently. To assign a value to a variable, enter a command line in one of these two forms name=value name="multiple-word-value" In the first form, value must be a single word that does not contain white space. To use the value of a variable anywhere in a command line, construct a reference to it in this form $name As an alternative, you can enclose the variable name in curly braces, as follows: ${name} The braces are required when the name is followed by a letter, digit, or underscore that is not part of the variable name. After processing each command line for variables to be substituted, the shell processes the results of any substitutions for white space characters so it can split that text into distinct arguments, in the same way that it splits all other command-line text into distinct arguments, before it forwards them to the command. Explicit null arguments can be supplied using a pair of double or single quotes with no enclosed text. Null arguments supplied this way are passed as distinct arguments to the command. Implicit null arguments can be supplied by specifying variables that have no values and by failing to enclose the variable reference inside double quote characters. Implicit null arguments are discarded rather than passed along to the command as distinct arguments. For variables established as ``automatic'' variables, the name of the variable need not be preceded by a dollar sign if it is given at the start of a command line: Each time a command line is entered, the first word is checked for matches with any of the automatic variables already defined. If there is a match, then the value is substituted. The process is not repeated on the replacement value. Whereas normal variables are created when they are assigned values, automatic variables must be declared as such. (See auto in ``Built-in Commands'' later in the ``Description'' 10 March 1993
StartupShell(8) StartupShell(8)section.) The variables autorecovery and autolaunch are examples of automatic variables. The following variables are established by the A/UX Startup shell: ? Contains the exit status returned by the last command executed. autolaunch Contains the command string associated with AutoLaunch in the Execute menu. autorecovery Contains the command string associated with AutoRecovery in the Execute menu. This command string can be set to invoke a command that helps verify the integrity of the root file system, making repairs as necessary. cwd Contains the current directory for the shell. cwroot Contains the current root directory for the shell. HOME Contains the default argument (home directory) for the cd and chdir commands. PATH Contains the search path for commands. (See ``Command-Line Processing'' earlier in the ``Description'' section.) PS1 Contains the prompt string, which by default is as follows: startup# ROOT Contains the default argument for the chroot command. TZ Contains the A/UX time-zone variable (see environ(5)). The shell gives initial values to all of these variables. The values persist across invocations of A/UX Startup even if the variable is not exported. (See export in ``Built-in Commands'' later in the ``Description'' section.) The limit on the number of variables that can exist is normally 20, but you can change the limit by modifying the A/UX Startup resource file. March 1993 11
StartupShell(8) StartupShell(8)Redirection The input and the output of a command can be redirected to files or devices through the use of specially interpreted metacharacters. Typically, a redirection metacharacter introduces the name of a file that you want to use as the source of input or the destination of output for a command. Without redirection, the display window is the default output location for standard output and error output. More precisely, file descriptor 1 is the default output location, and error output is permanently directed to the window, bypassing stderr (file descriptor 2). Each of the metacharacter constructions for redirection affects processing as described in the following list: <file Establishes the file indicated by file as the source of standard input (file descriptor 0) for the command line in which it is placed. >file Directs the standard output (file descriptor 1) from a command to the file indicated by file. If the file does not exist, it is created; otherwise, it is truncated to a length of zero characters. >>file Directs the standard output from a command to the file indicated by file. If the file exists, the system appends output to it; otherwise, the file is created. <&digit Establishes as the source for input the file (or device) currently associated with file descriptor digit for the command in which the descriptor is placed. >&digit Directs the standard output of a command to the file (or device) currently associated with the file descriptor digit for the command in which the descriptor is placed. <&- Closes the current source of standard input for a command. >&- Closes the current destination of standard output for a command. If any of these constructions is preceded by a digit, the file descriptor is specified by the digit (instead of the default 0 or 1). For example, the following line associates 12 March 1993
StartupShell(8) StartupShell(8)file descriptor 2 with the file currently associated with file descriptor 1: command 2>&1 The order in which redirections are specified is significant. The shell evaluates redirections from left to right. For example, the following line first associates file descriptor 1 with the file output and then associates file descriptor 2 with the file associated with file descriptor 1 (output). command 1>output 2>&1 If the order of redirections were reversed, file descriptor 2 would be associated with the terminal (assuming file descriptor 1 had been), and file descriptor 1 would be associated with file output. The environment passed to an executing program contains the same file descriptors as the shell, except those modified by input and output redirections on the command line. Devices, Partitions, and Pathnames In the A/UX environment, you gain access to multiple file systems by mounting file systems (block device files) on accessible directories. The A/UX Startup environment does not support mount. Instead, the A/UX pathname syntax has been extended with an optional prefixed device specification. A device specification has one of two forms: (scsi-id,disk,slice) (default) In the first form, scsi-id, disk, and slice are integers identifying a SCSI ID, a disk (or logical unit), and a partition (through a slice number). Note: For systems with multiple SCSI buses, it is not possible to address a specific bus using the provisions of A/UX Startup. Refer to gd(7) for a description of the search order that is employed and of the limitations that apply when the same SCSI ID is in use on several buses. The (default) prefix refers to a Root or Root&Usr partition of the disk containing the version of A/UX Startup that is currently running. When no device specification is used, the path is calculated relative to the current directory and current root March 1993 13
StartupShell(8) StartupShell(8)directory. The chroot command always changes the current directory to the new root directory specified. Character and block device files are not supported, because they depend on a mapping between device major numbers and devices, which is specific to the A/UX kernel (see intro(7)). Nevertheless, the open system call within this environment opens the following device files in raw (character) mode. /dev/console /dev/dsk/cscsi-idddisksslice /dev/floppy0 /dev/null /dev/rdsk/cscsi-idddisksslice /dev/rfloppy1 /dev/syscon /dev/systty Device files other than those listed cannot be opened from the A/UX Startup environment. Disk partitions are assigned slice numbers. The slice numbers are restricted to those between 0 and 31. The slice numbers act as a user-controllable cache of partitions. Partitions are assigned slice numbers automatically based on the partition attributes created by Apple HD SC Setup. Accordingly, the UNIX Root or UNIX Root&Usr partition is set to slice 0, the Swap partition is set to slice 1, and the UNIX Usr partition is set to slice 2. Slice number 31 always refers to the entire disk. You can also explicitly associate partitions and slice numbers by using pname. See dpme(4), bzb(4), gd(7), and pname(1M) for more details. Here is an example of a device specification and pathname: (1,0,2)/include/sys/param.h This example denotes the file param.h in the directory sys that is in the directory include that is in the root directory of the file system located in the partition associated with slice 2 of the device addressed as SCSI ID 1. Built-in Commands A built-in command does not run a corresponding program of the same name that resides in the file system somewhere. Rather, the shell interprets such a command and its arguments by itself. auto [ variable]... Establishes each of the named variables as automatic 14 March 1993
StartupShell(8) StartupShell(8)variables. When the name of an automatic variable is entered at the start of a command line, the A/UX Startup shell replaces the name with the command string it references and then executes that string. To avoid substitution when you enter the name of an automatic variable at the beginning of a command line, precede the first word with a backslash (\) to escape its special interpretation. If entered without any arguments, auto displays a list of all automatic variables and their values. autolaunch [launch-arg]... Executes the command string that has been assigned to the autolaunch variable after any launch-arg arguments have been appended to it. The autolaunch variable cannot be unset or converted into a normal variable, so it consistently behaves like a built-in function. The default assignment is autolaunch=launch, which causes the startup program named launch to be executed when autolaunch is entered. (See launch(8) for a description of the launch-arg arguments that can be specified.) Alternatively, you can choose AutoLaunch in the Execute menu to perform the same function (but with no opportunity to supply any launch-arg arguments). autorecovery [command-arg]... Executes the command string that has been assigned to the autorecovery variable after any command-arg arguments supplied have been appended to it. The automatic variable autorecovery cannot be unset or converted into a normal variable, so it consistently behaves as if it were a built-in function. Alternatively, you can choose AutoRecovery in the Execute menu to perform the same function (but with no opportunity to supply any command-arg arguments). boot Executes the autorecovery and autolaunch command strings. Alternatively, you can choose Boot in the Execute menu to perform the same function. If the autorecovery command string returns a nonzero exit value, autolaunch is not started. This command hides the shell window and displays the progress bar while A/UX is booting. cd [path] chdir [path] Change the current directory to that specified by path. If no argument is specified, the value of HOME is used as the specification for path. chroot [path] March 1993 15
StartupShell(8) StartupShell(8)Changes the current root directory to that specified by path. If no argument is specified, the value of ROOT is used as the specification for path. default Displays the SCSI ID of the disk referenced by the path prefix (default) echo [arg]... Displays the arg argument after unescaped command and variable substitutions take place. eject [drive] Ejects the disk in the specified disk drive. You must specify the value of the drive as either 0 or 1. exit Quits A/UX Startup (same as choosing Quit from the File menu). export [variable]... Establishes each of the named variables and their current values as part of the execution environment passed to subsequent commands. Furthermore, export causes the present values of the named variables to persist between invocations of A/UX Startup. If no names are specified, export lists all exported variables along with their present values. help [command] Displays the help information associated with a command. To see the help information that is available for various classes of commands, specify a class of commands, such as built-ins, rather than a single command. If you enter help with no arguments, a list of the classes of commands will be displayed. powerdown Shuts off the system power after an orderly shut down of all running applications (same as choosing Shut Down from the Execute menu). pwd Displays the current working directory, which is also the value of the variable cwd. readonly [variable]... Establishes each of the named variables as a read-only variable. Read-only variables can't be reset through reassignments. However, they can be unset and then redefined. If no variables are specified, readonly 16 March 1993
StartupShell(8) StartupShell(8)displays all the read-only variables along with their values. restart Restarts the system (same as choosing Restart from the Execute menu). set Displays all variables and their values. shutdown Shuts down the computer (same as the choosing Shut Down from the Execute menu). unauto [variable]... Removes the automatic attribute from each of the named variables. unexport [variable]... Removes the export attribute from each of the named variables. unset [variable]... Removes each of the named variables. None of the built-in shell variables can be unset. Built-in Variables Three of the built-in variables are set to be read-only variables: autorecovery, cwd, and ?. Two of the built-in variables are set to be automatic variables: autorecovery and autolaunch. Four of the built-in variables are initially established as exported variables so that they are passed to the execution environment of commands: HOME, PATH, ROOT, and TZ. The initial settings given to the built-in variables are those shown in the second column of the following list. Any reassignments you establish for the built-in variables will persist across invocations of A/UX Startup. None of the built-in variables can be unset or changed in terms of their attributes. Variable Initial Value___________________________________? 0autolaunch launchautorecoveryfsck -y -p /dev/defaultcwd /cwroot (default)/HOME /PATH (mac):|(mac):bin:PS1 startup#March 1993 17
StartupShell(8) StartupShell(8)ROOT (default)/ TZ PST8PDT Program Files Executable as Commands Except for a few commands, such as launch and boot, each command that runs within the A/UX Startup shell is an A/UX command rewritten for the A/UX Startup shell environment. For more information about the basically equivalent commands, refer to the Section 1M and to Section 1 of the A/UX Command Reference. The following programs can be executed from the A/UX Startup shell: cat chgrp chmod chown cp cpio date dd dp ed fsck fsdb kconfig launch ln ls mkdir mkfs mknod mv newfs od pname rm stty tar tunefs WARNINGS When using this shell, you have the equivalent of root privileges because permissions are not checked. Everything is accessible, and very few actions are disallowed. LIMITATIONS If you run the ls command for the directory /dev, you receive erroneous information for the character device 18 March 1993
StartupShell(8) StartupShell(8)files. However, you can see the correct information by prefixing a device specification to the directory. Accessing partitions through the mapping of slice numbers should also have been avoided, even though it reflects how A/UX accesses partitions. When you backspace over a tab character, the text is no longer correctly displayed. FILES /etc/auxstartuprc File containing A/UX Startup parameters related to password checking, such as those accounts that have full privileges for A/UX Startup SEE ALSO dp(1M), pname(1M), StartMonitor(1M), launch(8) auxstartuprc(4), bzb(4), dpme(4), environ(5), gd(7) in A/UX Programmer's Reference March 1993 19