3 novaboot - Boots a locally compiled operating system on a remote
10 B<novaboot> [option]... [--] script...
12 B<./script> [option]...
16 This program makes booting of a locally compiled operating system (OS)
17 (e.g. NOVA or Linux) on remote targets as simple as running a program
18 locally. It automates things like copying OS images to a TFTP server,
19 generation of bootloader configuration files, resetting of target
20 hardware or redirection of target's serial line to stdin/out. Novaboot
21 is highly configurable and it makes it easy to boot a single image on
22 different targets or different images on a single target.
24 Novaboot operation is controlled by command line options and by a so
25 called novaboot script, which can be thought as a generalization of
26 bootloader configuration files (see L</"NOVABOOT SCRIPT SYNTAX">).
27 Typical way of using novaboot is to make the novaboot script
28 executable and set its first line to I<#!/usr/bin/env novaboot>. Then,
29 booting a particular OS configuration becomes the same as executing a
30 local program - the novaboot script.
32 Novaboot uses configuration files to, among other things, define
33 command line options needed for different targets. Users typically use
34 only the B<-t>/B<--target> command line option to select the target.
35 Internally, this option expands to the pre-configured options.
36 Configuration files are searched at multiple places, which allows to
37 have per-system, per-user or per-project configurations. Configuration
38 file syntax is described in section L</"CONFIGURATION FILES">.
40 Simple examples of using C<novaboot>:
46 Run an OS in Qemu. This is can be specified with the B<--qemu> option.
47 Thus running C<novaboot --qemu myos> (or C<./myos --qemu> as described
48 above) will run Qemu and make it boot the configuration specified in
53 Create a bootloader configuration file (currently supported
54 bootloaders are GRUB, GRUB2, ISOLINUX, Pulsar and U-Boot) and copy it
55 with all other files needed for booting to a remote boot server. Then
56 use a TCP/IP-controlled relay/serial-to-TCP converter to reset the
57 target and receive its serial output.
59 ./myos --grub2 --server=192.168.1.1:/tftp --iprelay=192.168.1.2
63 Run DHCP and TFTP server on developer's machine to boot the target
68 This is useful when no network infrastructure is in place and
69 the target is connected directly to developer's box.
73 Create bootable ISO image.
75 novaboot --iso -- script1 script2
77 The created ISO image will have ISOLINUX bootloader installed on it
78 and the boot menu will allow selecting between I<script1> and
79 I<script2> configurations.
83 =head1 PHASES AND OPTIONS
85 Novaboot performs its work in several phases. Each phase can be
86 influenced by several command line options, certain phases can be
87 skipped. The list of phases (in the execution order) is as follows.
91 =item 1. L<Configuration reading|/Configuration reading phase>
93 =item 2. L<Command line processing|/Command line processing phase>
95 =item 3. L<Script preprocessing|/Script preprocessing phase>
97 =item 4. L<File generation|/File generation phase>
99 =item 5. L<Target connection|/Target connection check>
101 =item 6. L<File deployment|/File deployment phase>
103 =item 7. L<Target power-on and reset|/Target power-on and reset phase>
105 =item 8. L<Interaction with the bootloader|/Interaction with the bootloader on the target>
107 =item 9. L<Target interaction|/Target interaction phase>
111 Each phase is described in the following sections together with the
112 command line options that control it.
114 =head2 Configuration reading phase
116 After starting, novaboot reads configuration files. Their content is
117 described in section L</"CONFIGURATION FILES">. By default,
118 configuration is read from multiple locations. First from the system
119 configuration directory (F</etc/novaboot.d/>), second from the user
120 configuration file (F<~/.config/novaboot>) and third from F<.novaboot>
121 files along the path to the current directory. Alternatively, a single
122 configuration file specified with the B<-c> switch or with the
123 C<NOVABOOT_CONFIG> environment variable is read. The latter read files
124 override settings from the former ones.
126 The system configuration directory is determined by the content of
127 NOVABOOT_CONFIG_DIR environment variable and defaults to
128 F</etc/novaboot.d>. Files in this directory with names consisting
129 solely of English letters, numbers, dashes '-' and underscores '_'
130 (note that dot '.' is not included) are read in alphabetical order.
132 Then, the user configuration file is read from
133 F<$XDG_CONFIG_HOME/novaboot>. If C<$XDG_CONFIG_HOME> environemnt
134 variable is not set F<~/.config/novaboot> is read instead.
136 Finally, novaboot searches for files named F<.novaboot> starting from the
137 directory of the novaboot script (or working directory, see bellow)
138 and continuing upwards up to the root directory. The found
139 configuration files are then read in the opposite order (i.e. from the
140 root directory downwards). This allows to have, for example, a project
141 specific configuration in F<~/project/.novaboot>.
143 Note the difference between F<~/.config/novaboot> and F<~/.novaboot>.
144 The former one is read always, whereas the latter only when novaboot
145 script or working directory is under the C<$HOME> directory.
147 In certain cases, the location of the novaboot script cannot be
148 determined in this early phase. This happens either when the script is
149 read from the standard input or when novaboot is invoked explicitly as
150 in the example L</"4."> above. In this case the current working
151 directory is used as a starting point for configuration file search
152 instead of the novaboot script directory.
156 =item -c, --config=I<filename>
158 Use the specified configuration file instead of the default one(s).
162 =head2 Command line processing phase
168 Dump the current configuration to stdout end exit. Useful as an
169 initial template for a configuration file.
173 Print short (B<-h>) or long (B<--help>) help.
175 =item -t, --target=I<target>
177 This option serves as a user configurable shortcut for other novaboot
178 options. The effect of this option is the same as specifying the
179 options stored in the C<%targets> configuration variable under key
180 I<target>. See also L</"CONFIGURATION FILES">.
182 When this option is not given, novaboot tries to determine the target
183 to use from either B<NOVABOOT_TARGET> environment variable or from
184 B<$default_target> configuration file variable.
188 =head2 Script preprocessing phase
190 This phases allows to modify the parsed novaboot script before it is
191 used in the later phases.
195 =item -a, --append=I<parameters>
197 Append a string to the first C<load> line in the novaboot script. This
198 can be used to append parameters to the kernel's or root task's
199 command line. This option can appear multiple times.
203 Use F<bender> chainloader. Bender scans the PCI bus for PCI serial
204 ports and stores the information about them in the BIOS data area for
207 =item --chainloader=I<chainloader>
209 Specifies a chainloader that is loaded before the kernel and other
210 files specified in the novaboot script. E.g. 'bin/boot/bender
215 Print the modules to boot and their parameters after this phase
216 finishes. Then exit. This is useful for seeing the effect of other
217 options in this section.
219 =item -k, --kernel=F<file>
221 Replace the first word on the first C<load> line in the novaboot
224 =item --scriptmod=I<perl expression>
226 When novaboot script is read, I<perl expression> is executed for every
227 line (in $_ variable). For example, C<novaboot
228 --scriptmod=s/sigma0/omega6/g> replaces every occurrence of I<sigma0>
229 in the script with I<omega6>.
231 When this option is present, it overrides I<$script_modifier> variable
232 from the configuration file, which has the same effect. If this option
233 is given multiple times all expressions are evaluated in the command
238 =head2 File generation phase
240 In this phase, files needed for booting are generated in a so called
241 I<build directory> (see L</--build-dir>). In most cases configuration
242 for a bootloader is generated automatically by novaboot. It is also
243 possible to generate other files using I<heredoc> or I<"<"> syntax in
244 novaboot scripts. Finally, binaries can be generated in this phases by
245 running C<scons> or C<make>.
249 =item --build-dir=I<directory>
251 Overrides the default build directory location.
253 The default build directory location is determined as follows: If the
254 configuration file defines the C<$builddir> variable, its value is
255 used. Otherwise, it is the directory that contains the first processed
258 See also L</BUILDDIR> variable.
260 =item -g, --grub[=I<filename>]
262 Generates grub bootloader menu file. If the I<filename> is not
263 specified, F<menu.lst> is used. The I<filename> is relative to the
264 build directory (see B<--build-dir>).
266 =item --grub-preamble=I<prefix>
268 Specifies the I<preable> that is at the beginning of the generated
269 GRUB or GRUB2 config files. This is useful for specifying GRUB's
272 =item --prefix=I<prefix>
274 Specifies I<prefix> (e.g. F</srv/tftp>) that is put in front of every
275 file name in generated bootloader configuration files (or in U-Boot
278 If the I<prefix> contains string $NAME, it will be replaced with the
279 name of the novaboot script (see also B<--name>).
281 If the I<prefix> contains string $BUILDDIR, it will be replaced with
282 the build directory (see also B<--build-dir>).
286 Alias for B<--prefix>.
288 =item --grub2[=I<filename>]
290 Generate GRUB2 menu entry in I<filename>. If I<filename> is not
291 specified F<grub.cfg> is used. The content of the menu entry can be
292 customized with B<--grub-preamble>, B<--grub2-prolog> or
293 B<--grub_prefix> options.
295 In order to use the the generated menu entry on your development
296 machine that uses GRUB2, append the following snippet to
297 F</etc/grub.d/40_custom> file and regenerate your grub configuration,
298 i.e. run update-grub on Debian/Ubuntu.
300 if [ -f /path/to/nul/build/grub.cfg ]; then
301 source /path/to/nul/build/grub.cfg
304 =item --grub2-prolog=I<prolog>
306 Specifies text that is put at the beginning of the GRUB2 menu entry.
308 =item -m, --make[=make command]
310 Runs C<make> to build files that are not generated by novaboot itself.
312 =item --name=I<string>
314 Use the name I<string> instead of the name of the novaboot script.
315 This name is used for things like a title of grub menu or for the
316 server directory where the boot files are copied to.
320 Do not run external commands to generate files (i.e. "<" syntax and
321 C<run> keyword). This switch does not influence generation of files
322 specified with "<<WORD" syntax.
324 =item -p, --pulsar[=mac]
326 Generates pulsar bootloader configuration file named F<config-I<mac>>
327 The I<mac> string is typically a MAC address and defaults to
330 =item --scons[=scons command]
332 Runs C<scons> to build files that are not generated by novaboot
337 Strip I<rom://> prefix from command lines and generated config files.
338 The I<rom://> prefix is used by NUL. For NRE, it has to be stripped.
342 Exit novaboot after file generation phase.
346 =head2 Target connection check
348 If supported by the target, the connection to it is made and it is
349 checked whether the target is not occupied by another novaboot
354 =item --amt=I<"[user[:password]@]host[:port]>
356 Use Intel AMT technology to control the target machine. WS management
357 is used to powercycle it and Serial-Over-Lan (SOL) for input/output.
358 The hostname or (IP address) is given by the I<host> parameter. If
359 I<password> is not specified, environment variable AMT_PASSWORD is
360 used. The I<port> specifies a TCP port for SOL. If not specified, the
361 default is 16992. Default I<user> is admin.
363 =item --iprelay=I<addr[:port]>
365 Use TCP/IP relay and serial port to access the target's serial port
366 and powercycle it. The IP address of the relay is given by I<addr>
367 parameter. If I<port> is not specified, it default to 23.
369 Note: This option is supposed to work with HWG-ER02a IP relays.
371 =item -s, --serial[=device]
373 Target's serial line is connected to host's serial line (device). The
374 default value for device is F</dev/ttyUSB0>.
376 The value of this option is exported in NB_NOVABOOT environment
377 variable to all subprocesses run by C<novaboot>.
379 =item --stty=I<settings>
381 Specifies settings passed to C<stty> invoked on the serial line
382 specified with B<--serial> option. If this option is not given,
383 C<stty> is called with C<raw -crtscts -onlcr 115200> settings.
385 =item --remote-cmd=I<cmd>
387 Command that mediates connection to the target's serial line. For
388 example C<ssh server 'cu -l /dev/ttyS0'>.
390 =item --remote-expect=I<string>
392 Wait for reception of I<string> after establishing the remote
395 =item --remote-expect-silent=I<string>
397 The same as B<--remote-expect> except that the remote output is not
398 echoed to stdout while waiting for the I<string>. Everything after the
399 matched string is printed to stdout, so you may want to include line
400 end characters in the I<string> as well.
404 =head2 File deployment phase
406 In some setups, it is necessary to copy the files needed for booting
407 to a particular location, e.g. to a TFTP boot server or to the
412 =item -d, --dhcp-tftp
414 Turns your workstation into a DHCP and TFTP server so that the OS can
415 be booted via PXE BIOS (or similar mechanism) on the test machine
416 directly connected by a plain Ethernet cable to your workstation.
418 The DHCP and TFTP servers requires root privileges and C<novaboot>
419 uses C<sudo> command to obtain those. You can put the following to
420 I</etc/sudoers> to allow running the necessary commands without asking
423 Cmnd_Alias NOVABOOT = /bin/ip a add 10.23.23.1/24 dev eth0, /bin/ip l set dev eth0 up, /usr/sbin/dhcpd -d -cf dhcpd.conf -lf dhcpd.leases -pf dhcpd.pid, /usr/sbin/in.tftpd --listen --secure -v -v -v --pidfile tftpd.pid *, /usr/bin/touch dhcpd.leases, /usr/bin/pkill --pidfile=dhcpd.pid, /usr/bin/pkill --pidfile=tftpd.pid
424 your_login ALL=NOPASSWD: NOVABOOT
428 Starts a TFTP server on your workstation. This is similar to
429 B<--dhcp-tftp> except that DHCP server is not started.
431 The TFTP server require root privileges and C<novaboot> uses C<sudo>
432 command to obtain those. You can put the following to I</etc/sudoers>
433 to allow running the necessary commands without asking for password.
435 Cmnd_Alias NOVABOOT = /usr/sbin/in.tftpd --listen --secure -v -v -v --pidfile tftpd.pid *, /usr/bin/pkill --pidfile=tftpd.pid
436 your_login ALL=NOPASSWD: NOVABOOT
438 =item --tftp-port=I<port>
440 Port to run the TFTP server on. Implies B<--tftp>.
442 =item --iso[=filename]
444 Generates the ISO image that boots NOVA system via GRUB. If no filename
445 is given, the image is stored under I<NAME>.iso, where I<NAME> is the name
446 of the novaboot script (see also B<--name>).
448 =item --server[=[[user@]server:]path]
450 Copy all files needed for booting to another location. The files will
451 be copied (by B<rsync> tool) to the directory I<path>. If the I<path>
452 contains string $NAME, it will be replaced with the name of the
453 novaboot script (see also B<--name>).
455 =item --rsync-flags=I<flags>
457 Specifies which I<flags> are appended to F<rsync> command line when
458 copying files as a result of I<--server> option.
462 If B<--server> is used and its value ends with $NAME, then after
463 copying the files, a new bootloader configuration file (e.g. menu.lst)
464 is created at I<path-wo-name>, i.e. the path specified by B<--server>
465 with $NAME part removed. The content of the file is created by
466 concatenating all files of the same name from all subdirectories of
467 I<path-wo-name> found on the "server".
471 Use Intel AMT technology for IDE redirection. This allows the target
472 machine to boot from novaboot created ISO image. Implies B<--iso>.
474 The experimental C<amtider> utility needed by this option can be
475 obtained from https://github.com/wentasah/amtterm.
479 =head2 Target power-on and reset phase
481 At this point, the target is reset (or switched on/off). There is
482 several ways how this can be accomplished. Resetting a physical target
483 can currently be accomplished by the following options: B<--amt>,
484 B<--iprelay>, B<--reset-cmd>.
490 Switch on/off the target machine and exit. The script (if any) is
491 completely ignored. Currently it works only with B<--iprelay> or
494 =item -Q, --qemu[=I<qemu-binary>]
496 Boot the configuration in qemu. Optionally, the name of qemu binary
497 can be specified as a parameter.
499 =item --qemu-append=I<flags>
501 Append I<flags> to the default qemu flags (QEMU_FLAGS variable or
502 C<-cpu coreduo -smp 2>).
504 =item -q, --qemu-flags=I<flags>
506 Replace the default qemu flags (QEMU_FLAGS variable or C<-cpu coreduo
507 -smp 2>) with I<flags> specified here.
509 =item --reset-cmd=I<cmd>
511 Command that resets the target.
513 =item --no-reset, --reset
515 Disable/enable resetting of the target.
519 =head2 Interaction with the bootloader on the target
523 =item --uboot[=I<prompt>]
525 Interact with U-Boot bootloader to boot the thing described in the
526 novaboot script. I<prompt> specifies the U-Boot's prompt (default is
527 "=> ", other common prompts are "U-Boot> " or "U-Boot# ").
528 Implementation of this option is currently tied to a particular board
529 that we use. It may be subject to changes in the future!
533 Disable U-Boot interaction previously enabled with B<--uboot>.
537 Command(s) to send the U-Boot bootloader before loading the images and
538 booting them. This option can be given multiple times. After sending
539 commands from each option novaboot waits for U-Boot I<prompt>.
541 If the command contains string I<$NB_MYIP> then this string is
542 replaced by IPv4 address of eth0 interface. Similarly I<$NB_PREFIX> is
543 replaced with prefix given by B<--prefix>.
545 See also C<uboot> keyword in L</"NOVABOOT SCRIPT SYNTAX">).
547 =item --uboot-addr I<name>=I<address>
549 Load address of U-Boot's C<tftpboot> command for loading I<name>,
550 where name is one of I<kernel>, I<ramdisk> or I<fdt> (flattened device
553 The default addresses are ${I<name>_addr_r}, i.e. U-Boot environment
554 variables used by convention for this purpose.
556 =item --uboot-cmd=I<command>
558 Specifies U-Boot command used to execute the OS. If the command
559 contains strings C<$kernel_addr>, C<$ramdisk_addr>, C<$fdt_addr>,
560 these are replaced with the addresses configured with B<--uboot-addr>.
564 bootm $kernel_addr $ramdisk_addr $fdt_addr
566 or the C<UBOOT_CMD> variable if defined in the novaboot script.
570 =head2 Target interaction phase
572 In this phase, target's serial output is redirected to stdout and if
573 stdin is a TTY, it is redirected to the target's serial input allowing
574 interactive work with the target.
578 =item --exiton=I<string>
580 When I<string> is sent by the target, novaboot exits. This option can
581 be specified multiple times, in which case novaboot exits whenever
582 either of the specified strings is sent.
584 If I<string> is C<-re>, then the next B<--exiton>'s I<string> is
585 treated as regular expression. For example:
587 --exiton -re --exiton 'error:.*failed'
589 =item --exiton-re=I<regex>
591 The same as --exiton -re --exiton I<regex>.
593 =item --exiton-timeout=I<seconds>
595 By default B<--exiton> waits for the string match forever. When this
596 option is specified, "exiton" timeouts after the specifies number of
597 seconds and novaboot returns non-zero exit code.
599 =item -i, --interactive
601 Setup things for interactive use of target. Your terminal will be
602 switched to raw mode. In raw mode, your system does not process input
603 in any way (no echoing of entered characters, no interpretation
604 special characters). This, among others, means that Ctrl-C is passed
605 to the target and does no longer interrupt novaboot. Use "~~."
606 sequence to exit novaboot.
608 =item --no-interaction, --interaction
610 Skip resp. force target interaction phase. When skipped, novaboot exits
611 immediately when boot is initiated.
613 =item --expect=I<string>
615 When I<string> is received from the target, send the string specified
616 with the subsequent B<--send*> option to the target.
618 =item --expect-re=I<regex>
620 When target's output matches regular expression I<regex>, send the
621 string specified with the subsequent B<--send*> option to the target.
623 =item --expect-raw=I<perl-code>
625 Provides direct control over Perl's Expect module.
627 =item --send=I<string>
629 Send I<string> to the target after the previously specified
630 B<--expect*> was matched in the target's output. The I<string> may
631 contain escape sequences such as "\n".
633 Note that I<string> is actually interpreted by Perl, so it can contain
634 much more that escape sequences. This behavior may change in the
637 Example: C<--expect='login: ' --send='root\n'>
639 =item --sendcont=I<string>
641 Similar to B<--send> but continue expecting more input.
643 Example: C<--expect='Continue?' --sendcont='yes\n'>
645 =item --final-eol, --no-final-eol
647 By default, B<novaboot> always prints an end-of-line character at the
648 end of its execution in order to ensure that the output of programs
649 started after novaboot appears at the beginning of the line. When this
650 is not desired B<--no-final-eol> option can be used to override this
655 =head1 NOVABOOT SCRIPT SYNTAX
657 The syntax tries to mimic POSIX shell syntax. The syntax is defined
658 with the following rules.
660 Lines starting with "#" and empty lines are ignored.
662 Lines that end with "\" are concatenated with the following line after
663 removal of the final "\" and leading whitespace of the following line.
665 Lines of the form I<VARIABLE=...> (i.e. matching '^[A-Z_]+=' regular
666 expression) assign values to internal variables. See L</VARIABLES>
669 Lines starting with C<load> keyword represent modules to boot. The
670 word after C<load> is a file name (relative to the build directory
671 (see B<--build-dir>) of the module to load and the remaining words are
672 passed to it as the command line parameters.
674 When the C<load> line ends with "<<WORD" then the subsequent lines
675 until the line containing solely WORD are copied literally to the file
676 named on that line. This is similar to shell's heredoc feature.
678 When the C<load> line ends with "< CMD" then command CMD is executed
679 with F</bin/sh> and its standard output is stored in the file named on
680 that line. The SRCDIR variable in CMD's environment is set to the
681 absolute path of the directory containing the interpreted novaboot
684 Lines starting with C<run> keyword contain shell commands that are run
685 during file generation phase. This is the same as the "< CMD" syntax
686 for C<load> keyboard except that the command's output is not
687 redirected to a file. The ordering of commands is the same as they
688 appear in the novaboot script.
690 Lines starting with C<uboot> represent U-Boot commands that are sent
691 to the target if B<--uboot> option is given. Having a U-Boot line in
692 the novaboot script is the same as passing an equivalent
693 B<--uboot-init> option to novaboot. The C<uboot> keyword can be
694 suffixed with timeout specification. The syntax is C<uboot:Ns>, where
695 C<N> is the whole number of seconds. If the U-Boot command prompt does
696 not appear before the timeout, novaboot fails. The default timeout is
701 #!/usr/bin/env novaboot
702 load bzImage console=ttyS0,115200
703 run make -C buildroot
704 load rootfs.cpio < gen_cpio buildroot/images/rootfs.cpio "myapp->/etc/init.d/S99myapp"
706 Example (NOVA User Land - NUL):
708 #!/usr/bin/env novaboot
709 WVDESC=Example program
710 load bin/apps/sigma0.nul S0_DEFAULT script_start:1,1 \
711 verbose hostkeyb:0,0x60,1,12,2
712 load bin/apps/hello.nul
713 load hello.nulconfig <<EOF
714 sigma0::mem:16 name::/s0/log name::/s0/timer name::/s0/fs/rom ||
715 rom://bin/apps/hello.nul
718 This example will load three modules: F<sigma0.nul>, F<hello.nul> and
719 F<hello.nulconfig>. sigma0 receives some command line parameters and
720 F<hello.nulconfig> file is generated on the fly from the lines between
725 The following variables are interpreted in the novaboot script:
731 Novaboot chdir()s to this directory before file generation phase. The
732 directory name specified here is relative to the build directory
733 specified by other means (see L</--build-dir>).
737 Assigning this variable has the same effect as specifying L</--exiton>
740 =item HYPERVISOR_PARAMS
742 Parameters passed to hypervisor. The default value is "serial", unless
743 overridden in configuration file.
747 The kernel to use instead of the hypervisor specified in the
748 configuration file with the C<$hypervisor> variable. The value should
749 contain the name of the kernel image as well as its command line
750 parameters. If this variable is defined and non-empty, the variable
751 HYPERVISOR_PARAMS is not used.
755 If this variable is 1, the system is not booted. This is currently
756 only implemented for U-Boot bootloader where it is useful for
757 interacting with the bootloader without booting the system - e.g. for
762 Use a specific qemu binary (can be overridden with B<-Q>) and flags
763 when booting this script under qemu. If QEMU_FLAGS variable is also
764 specified flags specified in QEMU variable are replaced by those in
769 Use specific qemu flags (can be overridden with B<-q>).
777 Description of the WvTest-compliant program.
781 The timeout in seconds for WvTest harness. If no complete line appears
782 in the test output within the time specified here, the test fails. It
783 is necessary to specify this for long running tests that produce no
788 =head1 CONFIGURATION FILES
790 Novaboot can read its configuration from one or more files. By
791 default, novaboot looks for files in F</etc/novaboot.d>, file
792 F<~/.config/novaboot> and files named F<.novaboot> as described in
793 L</Configuration reading phase>. Alternatively, configuration file
794 location can be specified with the B<-c> switch or with the
795 NOVABOOT_CONFIG environment variable. The configuration file has Perl
796 syntax (i.e. it is better to put C<1;> as the last line) and should set
797 values of certain Perl variables. The current configuration can be
798 dumped with the B<--dump-config> switch. Some configuration variables
799 can be overridden by environment variables (see below) or by command
802 Supported configuration variables include:
808 Build directory location relative to the location of the configuration
811 =item $default_target
813 Default target (see below) to use when no target is explicitly
814 specified with the B<--target> command line option or
815 B<NOVABOOT_TARGET> environment variable.
819 Hash of target definitions to be used with the B<--target> option. The
820 key is the identifier of the target, the value is the string with
821 command line options. For instance, if the configuration file contains:
823 $targets{'mybox'} = '--server=boot:/tftproot --serial=/dev/ttyUSB0 --grub',
825 then the following two commands are equivalent:
827 ./myos --server=boot:/tftproot --serial=/dev/ttyUSB0 --grub
832 =head1 ENVIRONMENT VARIABLES
834 Some options can be specified not only via config file or command line
835 but also through environment variables. Environment variables override
836 the values from configuration file and command line parameters
837 override the environment variables.
841 =item NOVABOOT_CONFIG
843 Name of the novaboot configuration file to use instead of the default
846 =item NOVABOOT_CONFIG_DIR
848 Name of the novaboot configuration directory. When not specified
849 F</etc/novaboot.d> is used.
851 =item NOVABOOT_TARGET
853 Name of the novaboot target to use. This overrides the value of
854 B<$default_target> from the configuration file and can be overriden
855 with the B<--target> command line option.
857 =item NOVABOOT_BENDER
859 Defining this variable has the same meaning as B<--bender> option.
865 Michal Sojka <sojka@os.inf.tu-dresden.de>