Home
Developer Resources

Commonly Used Environment Variables

PDF Documents
Caution: This version of this document is no longer maintained. For the latest documentation, see http://www.qnx.com/developers/docs.

Appendix: Commonly Used Environment Variables

This appendix describes most of the environment variables that are commonly used under QNX Neutrino.

Use these links to locate an entry quickly:

A ¦ B ¦ C ¦ D ¦ E ¦ F ¦ G ¦ H ¦ I ¦ J ¦ L ¦ M ¦ N ¦ O ¦ P ¦ Q ¦ R ¦ S ¦ T ¦ U

For general information about setting environment variables, see the Configuring Your Environment chapter of the Neutrino User's Guide; for specific information, see the related utilities and programs.

A

ABLANG
A language code (e.g. en_CA for Canadian English) that a multilingual Photon application uses to determine what language to display.

For more information, see the International Language Support chapter of the Photon Programmer's Guide; for the currently supported codes, see /usr/photon/appbuilder/languages.def.

ABLPATH
A list of directories where you want a multilingual Photon application to search for translation files.

For more information, see the International Language Support chapter of the Photon Programmer's Guide, and ph in the Utilities Reference.

AB_RESOVRD
A path variable that lists directories to search for resource records for applications built with PhAB. See the Photon in Embedded Systems appendix of the Photon Programmer's Guide.
ACCEPT_LANGUAGE
Slinger sets this environment variable, for use by CGI scripts. It indicates the languages that can be read by the remote client.

For more information, see slinger in the Utilities Reference.

AUTOCONNECT
In order for the /etc/autoconnect to be run, this environment variable must be defined and set to 1.

For more information, see /etc/autoconnect in the Utilities Reference.

B

BROADCAST
The dhcp.client passes this environment variable to the /etc/dhcp/dhcp-up script. It indicates the client broadcast address that was obtained from the server.

C

CMD_INT
Slinger uses this environment variable to determine the pathname or name of the shell program used to interpret the string passed to the SSI command, exec cmd.

For more information, see slinger in the Utilities Reference.

COLUMNS
The number of character columns on the screen.
CONTENT_LENGTH
Slinger sets this environment variable, for use by CGI scripts. It indicates the length of the attached information in the case of a POST.

For more information, see slinger in the Utilities Reference.

CONTENT_TYPE
Slinger sets this environment variable, for use by CGI scripts. It indicates the type of the attached information in the case of a POST.

For more information, see slinger in the Utilities Reference.

D

DISPLAY
The name of the physical display on which to draw.
DL_DEBUG
Display debugging information about dynamically loaded libraries as they're opened.
DOCUMENT_ROOT
Slinger sets this environment variable, for use by CGI scripts. It indicates the location of data files. (Same as HTTPD_ROOT_DIR.)

For more information, see slinger in the Utilities Reference.

DONT_USE_LINK_UNLINK
Indicates to lpr to use rename() instead of link() or unlink().

E

EDITOR
The path of the editor you'd like to use by default.
EXINIT
Default elvis option settings. If set, the contents of this environment variable are executed on startup as a series of ex commands.

F

FILENAME
The dhcp.client passes this environment variable to the /etc/dhcp/dhcp-up script. It indicates the filename supplied in the server response.
FLASHQUALITY
The resolution for voyager to use with Macromedia Flash.
FONTSLEUTH
Internal use only.
FORWARDED
Slinger sets this environment variable, for use by CGI scripts. It indicates the name of the proxy server through which the web page is being processed.

For more information, see slinger in the Utilities Reference.

FROM
Slinger sets this environment variable, for use by CGI scripts. It indicates the name of the remote client user.

For more information, see slinger in the Utilities Reference.

G

GATEWAY
The dhcp.client passes this environment variable to the /etc/dhcp/dhcp-up script. It indicates the gateway that the client is to use.
GATEWAY_INTERFACE
Slinger sets this environment variable, for use by CGI scripts. It indicates the name and version of the Common Gateway Interface served on Slinger.

For more information, see slinger in the Utilities Reference.

GNUTARGET
Specifies the target (output file format) for GNU utilities. For more information, see the Selecting the Target System appendix of the Utilities Reference.
GZIP
A set of default options for gzip

H

HOME
Your current working directory when you first log in. It's specified as one of the fields for each user in /etc/passwd. For more information, see passwd in the Utilities Reference.
HOSTALIASES
The name of a file containing aliases for hosts. For more information, see gethostbyname() in the Library Reference.
HOSTNAME
The name of the host machine.
HTTPD_ROOT_DIR
The name of the directory where Slinger looks for data files. The default is /usr/local/httpd.

For more information, see slinger in the Utilities Reference.

HTTPD_ROOT_DOC
The name of the root document (e.g. index.html) in Slinger.

For more information, see slinger in the Utilities Reference.

HTTPD_SCRIPTALIAS
The directory where Slinger looks for the CGI executables.

For more information, see slinger in the Utilities Reference.

HTTP_ACCEPT
Slinger sets this environment variable, for use by CGI scripts. It indicates the MIME types that the client accepts, as given by HTTP headers.

For more information, see slinger in the Utilities Reference.

HTTP_USER_AGENT
Slinger sets this environment variable, for use by CGI scripts. It indicates the browser that the client is using to send requests.

For more information, see slinger in the Utilities Reference.

I

INTERFACE
The dhcp.client passes this environment variable to the /etc/dhcp/dhcp-up script. It indicates the interface that was configured (e.g. en0).
IOPORT
The pccard-launch utility sets this environment variable to indicate the hex address of the I/O port (e.g. 320).
IOPORT2
The pccard-launch utility sets this environment variable to indicate the hex address of the second I/O port, if assigned.
IOPORT2SZ
The pccard-launch utility sets this environment variable to indicate the size of the second I/O port, if assigned.
IOPORTSZ
The pccard-launch utility sets this environment variable to indicate the size of the I/O port (e.g. 32).
IPADDRESS
The dhcp.client passes this environment variable to the /etc/dhcp/dhcp-up script. It indicates the client IP address that was obtained from the server.
IRQ
The pccard-launch utility sets this environment variable to indicate the IRQ of the device.
IVE_HOME
Used by Java VM.

J

J9PLUGIN_ARGS
Arguments passed to Browser Java plugins.

L

LANG
The locale to use for the locale categories.

Note: QNX Neutrino currently supports only the POSIX (i.e. C) locale.

LC_TYPE
The locale for character classification, used by uniq to determine the characters constituting a blank in the current locale.

Note: QNX Neutrino currently supports only the POSIX (i.e. C) locale.

LDEMULATION
Specifies the linker emulation. For more information, see the Selecting the Target System appendix of the Utilities Reference.
LD_LIBRARY_PATH
A path to search for shared libraries for a native linker. For more information, see ld in the Utilities Reference
LD_PRELOAD
A path to load shared libraries on an ELF system before other libraries are loaded. The libraries are listed using colon as delimiters. This can also be used to selectively override functions in other shared libraries. For setuid/setgid ELF binaries, only libraries in the standard search directories that are also setuid will be loaded. For more information, see ld in the Utilities Reference.
LD_RUN_PATH
A path to search for shared libraries on an ELF system. For more information, see ld in the Utilities Reference
LEASEEXPIRES
The dhcp.client passes this environment variable to the /etc/dhcp/dhcp-up script. It indicates the time at which the lease expires.
LEASEOBTAINED
The dhcp.client passes this environment variable to the /etc/dhcp/dhcp-up script. It indicates the time at which the lease was obtained.
LESS
Options that you want to pass to less automatically.
LESSEDIT
The editor prototype string (used for the v command in less).
LINES
The number of character lines on the screen.
LOCALDOMAIN
The local domain name. For more information, see res_init() in the Library Reference.
LOGNAME
The userid you used to login; the same as USERNAME.

M

MAKEFLAGS
A set of default options for make.
MIBFILE
The location of the mib.txt file.
MKIFS_PATH
A colon-separated list of directories that mkifs should use to search for host files to be included in an OS image.
MORE
Default options for more

N

NAMESERVER1, NAMESERVER2
The dhcp.client passes these environment variables to the /etc/dhcp/dhcp-up script. They indicate the nameservers that the client is to use.
NAME_MAX
The maximum permitted length of a component of a pathname.
NETMASK
The dhcp.client passes this environment variable to the /etc/dhcp/dhcp-up script. It indicates the client netmask that was obtained from the server.

O

OPTIONx
The dhcp.client passes these additional environment variables (where x is the option number) to the /etc/dhcp/dhcp-up script.

P

PATH
A colon-separated list of directories that are searched when the shell looks for commands and .'d files. An empty string resulting from a leading or trailing colon, or two adjacent colons is treated as a ., the current directory.

For more information, see ksh in the Utilities Reference.

PATH_INFO
Slinger sets this environment variable, for use by CGI scripts. It indicates extra path information sent.

For more information, see slinger in the Utilities Reference.

PATH_MAX
The maximum permitted length of a pathname.
PATH_TRANSLATED
Slinger sets this environment variable, for use by CGI scripts. It's the same as the PATH_INFO appended to the pathname in HTTPD_ROOT_DIR.

For more information, see slinger in the Utilities Reference.

PHEXIT_DISABLE
Set this environment variable to turn off the Photon Login dialog's Exit button so that users won't be able to exit to text mode.

For more information, see phlogin in the Utilities Reference.

PHFONT
The registered name of the font server (e.g. /dev/phfont).

For more information, see ph in the Utilities Reference.

PHFONT_USE_EXTERNAL
If this environment variable exists, io-graphics runs the font manager as a separate process (see phfont) instead of using phfont.so. You should set this environment variable for systems that have remote clients accessing font services on the host machine (e.g. phindows, phditto).
PHFONTMEM
The size of an area in shared memory to set up between the task and the Photon font server for returning text bitmaps (normally required only by graphics drivers). For more information, see PfAttach() in the Photon Library Reference.
PHFONTOPTS
Options to pass to the Photon font server. For more information, see phfont.
PHGFX
The full command that you want the ph script to use instead of the default commands to start the graphics driver.
PHINPUT
The full command that you want the ph script to use instead of the default commands to start the input driver.
PHINSTANCE
The number of times that Photon has been instantiated. For more information, see phlogin in the Utilities Reference.
PHOTON
The name of the Photon device (usually /dev/photon). For more information, see ph in the Utilities Reference.
PHOTONOPTS
(Windows-hosted version only) Additional options you want to pass to the Photon server when it starts.
PHOTON_PATH
The name of the root directory containing Photon files (usually /usr/photon). For more information, see ph in the Utilities Reference.
PHOTON2_PATH
Internal use only.
PHSTART
Internal use only.
PHTK_PATH
Internal use only.
PHWM
The name of the Window Manager to start when you start Photon. For more information, see ph in the Utilities Reference.
PHWMEXIT
If you set this environment variable, Photon disables the confirmation dialog when you exit Photon. For more information, see pwm in the Utilities Reference.
PHWMOPTS
Options you want to pass to the window manager when it starts. For more information, see pwm in the Utilities Reference.
POSIX_STRICT
Indicates that utilities must interpret options according to POSIX specifications.
PRINTER
The name of the default printer, used by lpr.
PROCESSOR
Specifies the target CPU when building an image filesystem. If not set, the default is the same as the CPU of the host system (e.g. x86). For more information, see mkifs in the Utilities Reference.
PTERMPAL
The pathname of the palette file for pterm.
PTERMRC
The name of a local configuration file for pterm.
PWMOPTS
(Windows-hosted version only) Options you want to pass to the window manager when it starts. For more information, see pwm in the Utilities Reference.
PWM_PRINTSCRN_APP
The application to start when the Print Scrn key is pressed. The default is snapshot.

Q

QCC_CONF_PATH
The name of the directory that contains the configuration files for qcc.
QNX_HOST
The location of host-specific files for Windows and Solaris hosts.
QNX_TARGET
The location of target backends on the host machine.
QUERY_STRING
Slinger sets this environment variable, for use by CGI scripts. It indicates the raw query string sent from the remote client.

For more information, see slinger in the Utilities Reference.

R

REFERER
Slinger sets this environment variable, for use by CGI scripts. It indicates the URL of the HTML page that referred the remote client to this web page.

For more information, see slinger in the Utilities Reference.

REMOTE_ADDR
Slinger sets this environment variable, for use by CGI scripts. It indicates the IP address of the remote client.

For more information, see slinger in the Utilities Reference.

REMOTE_HOST
Slinger sets this environment variable, for use by CGI scripts. It indicates the hostname of the remote client.

For more information, see slinger in the Utilities Reference.

REMOTE_IDENT
Slinger sets this environment variable, for use by CGI scripts. It indicates the remote username if supporting RFC 931 identification.

For more information, see slinger in the Utilities Reference.

REMOTE_PORT
Slinger sets this environment variable, for use by CGI scripts. It indicates the port of the remote client.

For more information, see slinger in the Utilities Reference.

REMOTE_USER
Slinger sets this environment variable, for use by CGI scripts. It indicates the username used to validate authentication from the remote client.

For more information, see slinger in the Utilities Reference.

REQUEST_METHOD
Slinger sets this environment variable, for use by CGI scripts. It indicates the method by which the current web page was requested (GET or POST).

For more information, see slinger in the Utilities Reference.

RESCONF
An way of overriding configuration strings in the resolv.conf file.

S

SCRIPT_NAME
Slinger sets this environment variable, for use by CGI scripts. It indicates the name of the script being executed.

For more information, see slinger in the Utilities Reference.

SERVER
The dhcp.client passes this environment variable to the /etc/dhcp/dhcp-up script. It indicates the server's IP address.
SERVER_ADMIN
Slinger sets this environment variable, for use by CGI scripts. It indicates the contact information of the administrator of Slinger specified by Slinger's -a option.

For more information, see slinger in the Utilities Reference.

SERVER_NAME
Slinger sets this environment variable, for use by CGI scripts. It indicates the name of the computer where Slinger is running.

For more information, see slinger in the Utilities Reference.

SERVER_PORT
Slinger sets this environment variable, for use by CGI scripts. It indicates the IP port that Slinger is answering on.

For more information, see slinger in the Utilities Reference.

SERVER_PROTOCOL
Slinger sets this environment variable, for use by CGI scripts. It indicates the name and version of HTTP served on Slinger.

For more information, see slinger in the Utilities Reference.

SERVER_ROOT
Slinger sets this environment variable, for use by CGI scripts. It indicates Slinger's current working directory.

For more information, see slinger in the Utilities Reference.

SERVER_SOFTWARE
Slinger sets this environment variable, for use by CGI scripts. It indicates the name of the Slinger software.

For more information, see slinger in the Utilities Reference.

SHELL
The pathname of the command interpreter, or shell, that you want to use. It's set by login.
SMICINCL
A list of directories to search for MIB modules. For more information, see smic in the Utilities Reference.
SNMPCONFIGFILE
The pathname of the snmpd.conf file.
SOCKET
The pccard-launch utility sets this environment variable to indicate the socket where the card is inserted.
SOCKS_NS
The IP address of the domain nameserver that should be used for name resolution by rftp and rtelnet.
SOCKS_SERVER
The name or IP address of the SOCKS proxy server host to use, overriding the default server compiled into rftp and rtelnet.
SUFFIX
If this environment variable exists, the SNMP utilities print only the last element of all object IDs with a symbolic name. For more information, see snmpget in the Utilities Reference.
SYSLOG
The node on which syslogd is running.
SYSNAME
The name of the system.

T

TERM
The terminal type.
TERMINFO
The name of the directory for terminfo files; see tic in the Utilities Reference.
TMPDIR
The name of a directory where utilities can create temporary files.
TZ
The timezone definition; see "Setting the time zone" in the Configuring Your Environment chapter of the Neutrino User's Guide.

U

USER
The userid you used to login; the same as LOGNAME.
USER_NAME
Internal use only.