Category Archives: Linux Man Pages


SORT(1) User Commands SORT(1)

sort – sort lines of text files

sort [OPTION]… [FILE]…

Write sorted concatenation of all FILE(s) to standard output.

Mandatory arguments to long options are mandatory for short options
too. Ordering options:

-b, –ignore-leading-blanks
ignore leading blanks

-d, –dictionary-order
consider only blanks and alphanumeric characters

-f, –ignore-case
fold lower case to upper case characters

-g, –general-numeric-sort
compare according to general numerical value

-i, –ignore-nonprinting
consider only printable characters

-M, –month-sort
compare (unknown) < `JAN’ < … < `DEC’

-n, –numeric-sort
compare according to string numerical value

-R, –random-sort
sort by random hash of keys

get random bytes from FILE (default /dev/urandom)

sort according to WORD: general-numeric -g, month -M, numeric
-n, random -R

-r, –reverse
reverse the result of comparisons

Other options:

-c, –check, –check=diagnose-first
check for sorted input; do not sort

-C, –check=quiet, –check=silent
like -c, but do not report first bad line

compress temporaries with PROG; decompress them with PROG -d

-k, –key=POS1[,POS2]
start a key at POS1, end it at POS2 (origin 1)

-m, –merge
merge already sorted files; do not sort

-o, –output=FILE
write result to FILE instead of standard output

-s, –stable
stabilize sort by disabling last-resort comparison

-S, –buffer-size=SIZE
use SIZE for main memory buffer

-t, –field-separator=SEP
use SEP instead of non-blank to blank transition

-T, –temporary-directory=DIR
use DIR for temporaries, not $TMPDIR or /tmp; multiple options
specify multiple directories

-u, –unique
with -c, check for strict ordering; without -c, output only the
first of an equal run

-z, –zero-terminated
end lines with 0 byte, not newline

–help display this help and exit

output version information and exit

POS is F[.C][OPTS], where F is the field number and C the character
position in the field; both are origin 1. If neither -t nor -b is in
effect, characters in a field are counted from the beginning of the
preceding whitespace. OPTS is one or more single-letter ordering
options, which override global ordering options for that key. If no
key is given, use the entire line as the key.

SIZE may be followed by the following multiplicative suffixes: % 1% of
memory, b 1, K 1024 (default), and so on for M, G, T, P, E, Z, Y.

With no FILE, or when FILE is -, read standard input.

*** WARNING *** The locale specified by the environment affects sort
order. Set LC_ALL=C to get the traditional sort order that uses native
byte values.

Written by Mike Haertel and Paul Eggert.

Report bugs to <>.

Copyright © 2008 Free Software Foundation, Inc. License GPLv3+: GNU
GPL version 3 or later <>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

The full documentation for sort is maintained as a Texinfo manual. If
the info and sort programs are properly installed at your site, the

info coreutils ‘sort invocation’

should give you access to the complete manual.

GNU coreutils 6.12 December 2008 SORT(1)

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wvdial – PPP dialer with built-in intelligence.


wvdial –help | –version | –chat | –config | option=value | –no-
syslog | section…


wvdial is an intelligent PPP dialer, which means that it dials a modem
and starts PPP in order to connect to the Internet. It is something
like the chat(8) program, except that it uses heuristics to guess how
to dial and log into your server rather than forcing you to write a
login script.

When wvdial starts, it first loads its configuration from
/etc/wvdial.conf and ~/.wvdialrc which contains basic information about
the modem port, speed, and init string, along with information about
your Internet Service Provider (ISP), such as the phone number, your
username, and your password.

Then it initializes your modem and dials the server and waits for a
connection (a CONNECT string from the modem). It understands and
responds to typical connection problems (like BUSY and NO DIALTONE).

Any time after connecting, wvdial will start PPP if it sees a PPP
sequence from the server. Otherwise, it tries to convince the server
to start PPP by doing the following:

– responding to any login/password prompts it sees;

– interpreting “choose one of the following”-style menus;

– eventually, sending the word “ppp” (a common terminal server com-

If all of this fails, wvdial just runs pppd(8) and hopes for the best.
It will bring up the connection, and then wait patiently for you to
drop the link by pressin CTRL-C.


Several options are recognized by wvdial.

–chat Run wvdial as a chat replacement from within pppd, instead of
the more normal method of having wvdial negotiate the connection
and then call pppd.

Override the Remote Name setting in the dialer configuration
section of the configuration file. This is mainly useful when
you dial to multiple systems with the same user name and pass-
word, and you don’t want to use inheritance to override this
setting (which is the recommended way to do it).

–config [configfile]
Run wvdial with configfile as the configuration file (instead of
/etc/wvdial.conf). This is mainly useful only if you want to
have per-user configurations, or you want to avoid having dial-
up information (usernames, passwords, calling card numbers,
etc.) in a system wide configuration file.

Don’t output debug information to the syslog daemon (only useful
together with –chat).

–help Prints a short message describing how to use wvdial and exits.

Displays wvdial’s version number and exits.

wvdial is normally run without command line options, in which case it
reads its configuration from the [Dialer Defaults] section of
/etc/wvdial.conf. (The configuration file is described in more detail
in wvdial.conf(5) manual page.)

One or more sections of /etc/wvdial.conf may be specified on the com-
mand line. Settings in these sections will override settings in
[Dialer Defaults].

For example, the command:
wvdial phone2

will read default options from the [Dialer Defaults] section, then
override any or all of the options with those found in the [Dialer
phone2] section.

If more than one section is specified, they are processed in the order
they are given. Each section will override all the sections that came
before it.

For example, the command:
wvdial phone2 pulse shh

will read default options from the [Dialer Defaults] section, then
override any or all of the options with those found in the [Dialer
phone2] section, followed by the [Dialer pulse] section, and lastly the
[Dialer shh] section.

Using this method, it is possible to easily configure wvdial to switch
between different internet providers, modem init strings, account
names, and so on without specifying the same configuration information
over and over.


“Intelligent” programs are frustrating when they don’t work right.
This version of wvdial has only minimal support for disabling or over-
riding its “intelligence”, with the “Stupid Mode”, “Login Prompt”, and
“Password Prompt” options. So, in general if you have a nice ISP, it
will probably work, and if you have a weird ISP, it might not.

Still, it’s not much good if it doesn’t work for you, right? Don’t be
fooled by the fact that wvdial finally made it to version 1.00; it
could well contain many bugs and misfeatures. Let us know if you have
problems by sending e-mail to .

Also, there is now a mailing list for discussion about wvdial. If you
are having problems, or have anything else to say, send e-mail to

You may encounter some error messages if you don’t have write access to
/etc/ppp/pap-secrets and /etc/ppp/chap-secrets. Unfortunately, there’s
really no nice way around this yet.


Configuration file which contains modem, dialing, and login
information. See

Serial port devices.

Required for correct authentication in pppd version 2.3.0 or

Contains a list of usernames and passwords used by pppd for
authentication. wvdial maintains this list automatically.


Dave Coombs and Avery Pennarun for Net Integration Technologies, as
part of the Worldvisions Weaver project. We would like to thank SuSE
and RedHat for adding a number of various cool features to Thanks guys!


wvdial.conf(5), wvdialconf(1), pppd(8), chat(8).


Worldvisions WvDial May 2001 WVDIAL(1)

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modprobe – program to add and remove modules from the Linux Kernel

modprobe [ -v ] [ -V ] [ -C config-file ] [ -n ] [ -i ] [ -q ] [ -o
modulename ] [ modulename ] [ module parameters … ]

modprobe [ -r ] [ -v ] [ -n ] [ -i ] [ modulename … ]

modprobe [ -l ] [ -t dirname ] [ wildcard ]

modprobe [ -c ]

modprobe [ –dump-modversions ]

modprobe intelligently adds or removes a module from the Linux kernel:
note that for convenience, there is no difference between _ and – in
module names. modprobe looks in the module directory /lib/mod-
ules/`uname -r` for all the modules and other files, except for the
optional /etc/modprobe.conf configuration file and /etc/modprobe.d
directory (see modprobe.conf(5)). modprobe will also use module options
specified on the kernel command line in the form of <module>.option>.

Note that this version of modprobe does not do anything to the module
itself: the work of resolving symbols and understanding parameters is
done inside the kernel. So module failure is sometimes accompanied by
a kernel message: see dmesg(8).

modprobe expects an up-to-date modules.dep file, as generated by depmod
(see depmod(8)). This file lists what other modules each module needs
(if any), and modprobe uses this to add or remove these dependencies
automatically. See modules.dep(5)).

If any arguments are given after the modulename, they are passed to the
kernel (in addition to any options listed in the configuration file).

-v –verbose
Print messages about what the program is doing. Usually mod-
probe only prints messages if something goes wrong.

This option is passed through install or remove commands to
other modprobe commands in the MODPROBE_OPTIONS environment

-C –config
This option overrides the default configuration file (/etc/mod-
probe.conf or /etc/modprobe.d/ if that isn’t found).

This option is passed through install or remove commands to
other modprobe commands in the MODPROBE_OPTIONS environment

-c –showconfig
Dump out the configuration file and exit.

-n –dry-run
This option does everything but actually insert or delete the
modules (or run the install or remove commands). Combined with
-v, it is useful for debugging problems.

-i –ignore-install –ignore-remove
This option causes modprobe to ignore install and remove com-
mands in the configuration file (if any), for the module on the
command line (any dependent modules are still subject to com-
mands set for them in the configuration file). See mod-

-q –quiet
Normally modprobe will report an error if you try to remove or
insert a module it can’t find (and isn’t an alias or
install/remove command). With this flag, modprobe will simply
ignore any bogus names (the kernel uses this to opportunisti-
cally probe for modules which might exist).

-r –remove
This option causes modprobe to remove, rather than insert a mod-
ule. If the modules it depends on are also unused, modprobe
will try to remove them, too. Unlike insertion, more than one
module can be specified on the command line (it does not make
sense to specify module parameters when removing modules).

There is usually no reason to remove modules, but some buggy
modules require it. Your kernel may not support removal of mod-

-w –wait
This option is applicable only with the -r or –remove option.
It causes modprobe to block in the kernel (within the kernel
module handling code itself) waiting for the specified modules’
reference count to reach zero. Default operation is for modprobe
to operate like rmmod, which exits with EWOULDBLOCK if the mod-
ules reference count is non-zero.

-V –version
Show version of program, and exit. See below for caveats when
run on older kernels.

-f –force
Try to strip any versioning information from the module, which
might otherwise stop it from loading: this is the same as using
both –force-vermagic and –force-modversion. Naturally, these
checks are there for your protection, so using this option is

This applies to any modules inserted: both the module (or alias)
on the command line, and any modules it depends on.

Every module contains a small string containing important infor-
mation, such as the kernel and compiler versions. If a module
fails to load and the kernel complains that the “version magic”
doesn’t match, you can use this option to remove it. Naturally,
this check is there for your protection, so this using option is

This applies to any modules inserted: both the module (or alias)
on the command line, and any modules it depends on.

When modules are compiled with CONFIG_MODVERSIONS set, a section
is created detailing the versions of every interface used by (or
supplied by) the module. If a module fails to load and the ker-
nel complains that the module disagrees about a version of some
interface, you can use “–force-modversion” to remove the ver-
sion information altogether. Naturally, this check is there for
your protection, so using this option is dangerous.

This applies any modules inserted: both the module (or alias) on
the command line, and any modules it depends on.

-l –list
List all modules matching the given wildcard (or “*” if no wild-
card is given). This option is provided for backwards compati-
bility: see find(1) and basename(1) for a more flexible alterna-

-a –all
Insert all module names on the command line.

-t –type
Restrict -l to modules in directories matching the dirname
given. This option is provided for backwards compatibility: see
find(1) and basename(1) or a more flexible alternative.

-s –syslog
This option causes any error messages to go through the syslog
mechanism (as LOG_DAEMON with level LOG_NOTICE) rather than to
standard error. This is also automatically enabled when stderr
is unavailable.

This option is passed through install or remove commands to
other modprobe commands in the MODPROBE_OPTIONS environment

Set the kernel version, rather than using uname(2) to decide on
the kernel version (which dictates where to find the modules).
This also disables backwards compatibility checks (so mod-
probe.old(8) will never be run).

List the dependencies of a module (or alias), including the mod-
ule itself. This produces a (possibly empty) set of module
filenames, one per line, each starting with “insmod”. Install
commands which apply are shown prefixed by “install”. It does
not run any of the install commands. Note that modinfo(8) can
be used to extract dependencies of a module from the module
itself, but knows nothing of aliases or install commands.

-o –name
This option tries to rename the module which is being inserted
into the kernel. Some testing modules can usefully be inserted
multiple times, but the kernel refuses to have two modules of
the same name. Normally, modules should not require multiple
insertions, as that would make them useless if there were no
module support.

Normally, modprobe will succeed (and do nothing) if told to
insert a module which is already present, or remove a module
which isn’t present. This is backwards compatible with the
modutils, and ideal for simple scripts. However, more compli-
cated scripts often want to know whether modprobe really did
something: this option makes modprobe fail for that case.

Print out a list of module versioning information required by a
module. This option is commonly used by distributions in order
to package up a Linuxx kernel module using module versioning

Apply a matchin blacklist entry also to a request by module
name, not only to a request by an alias.

Load unsupported modules even if disabled in configuration.

modprobe returns 0 on success, 1 on an unspecified error and 2 if the
module is not supported. Use the –allow-unsupported-modules option to
force using an unsupported module.

This version of modprobe is for kernels 2.5.48 and above. If it
detects a kernel with support for old-style modules (for which much of
the work was done in userspace), it will attempt to run modprobe.old in
its place, so it is completely transparent to the user.

The MODPROBE_OPTIONS environment variable can also be used to pass
arguments to modprobe.

This manual page Copyright 2002, Rusty Russell, IBM Corporation.

modprobe.conf(5), lsmod(8), modprobe.old(8)

01 December 2008 MODPROBE(8)

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mkdirhier – makes a directory hierarchy

mkdirhier directory …

The mkdirhier command creates the specified directories. Unlike mkdir
if any of the parent directories of the specified directory do not
exist, it creates them as well.


X Version 11 imake 1.0.2 MKDIRHIER(1)

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modinfo – program to show information about a Linux Kernel module

modinfo [ -0 ] [ -F field ] [ -k kernel ] [ modulename|filename … ]

modinfo -V

modinfo -h

modinfo extracts information from the Linux Kernel modules given on the
command line. If the module name is not a filename, then the /lib/mod-
ules/version directory is searched, as done by modprobe(8).

modinfo by default lists each attribute of the module in form fieldname
: value, for easy reading. The filename is listed the same way
(although it’s not really an attribute).

This version of modinfo can understand modules of any Linux Kernel

-V –version
Print the modinfo version. Note BACKWARDS COMPATIBILITY below:
you might be printing the version of modinfo.old.

-F –field
Only print this field value, one per line. This is most useful
for scripts. Field names are case-insenitive. Common fields
(which may not be in every module) include author, description,
license, param, depends, and alias. There are often multiple
param, alias and depends fields. The special field filename
lists the filename of the module.

-k kernel
Provide information about a kernel other than the running one.
This is particularly useful for distributions needing to extract
information from a newly installed (but not yet running) set of
kernel modules. For example, you wish to find which firmware
files are needed by various modules in a new kernel for which
you must make an initrd image prior to booting.

-0 –null
Use the ASCII zero character to separate field values, instead
of a new line. This is useful for scripts, since a new line can
theoretically appear inside a field.

-a -d -l -p -n
These are shortcuts for author, description, license. param and
filename respectively, to ease the transition from the old modu-
tils modinfo.

This version of modinfo is for kernel modules 2.5.48 and above. If it
detects a kernel with support for old-style modules, it will attempt to
run modprobe.old in its place, so it is completely transparent to the

Note that the output of this version of modinfo is simpler and more
regular than the older version: scripts attempting to use the default
output may get confused with complex fields.

You can force the new modinfo to always be used, by setting the
NEW_MODINFO environment variable.

This manual page Copyright 2003, Rusty Russell, IBM Corporation.

modprobe(8), modinfo.old(8)

22 August 2008 MODINFO(8)

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