Computer Science
ncftp(1) ncftp(1)
NAME
ncftp - Browser program for the File Transfer Protocol
SYNOPSIS
ncftp [host]
ncftp [ftp://host.name/directory/]
DESCRIPTION
The purpose of ncftp is to provide a powerful and flexible
interface to the Internet standard File Transfer Protocol.
It is intended to replace the stock ftp program that comes
with the system.
Although the program appears to be rather spartan, you'll
find that ncftp has a wealth of valuable performance and
usage features. The program was designed with an emphasis
on usability, and it does as much as it can for you auto-
matically so you can do what you expect to do with a file
transfer program, which is transfer files between two
interconnected systems.
Some of the cooler features include progress meters, file-
name completion, command-line editing, background process-
ing, auto-resume downloads, bookmarking, cached directory
listings, host redialing, working with firewalls and prox-
ies, downloading entire directory trees, etc., etc.
The ncftp distribution comes with the useful utility pro-
grams ncftpget(1) and ncftpput(1) which were designed to
do command-line FTP. In particular, they are very handy
for shell scripts. This version of ncftp no longer does
command-line FTP, since the main ncftp program is more of
a browser-type program.
INTRODUCTION TO THE COMMAND SHELL
Upon running the program you are presented a command
prompt where you type commands to the program's shell.
Usually you will want to open a remote filesystem to
transfer files to and from your local machine's filesys-
tem. To do that, you need to know the symbolic name of
the remote system, or its Internet Protocol (IP) address.
For example, a symbolic name might be ``typhoon.unl.edu,''
and its IP address could be ``129.93.33.24.'' To open a
connection to that system, you use the program's open com-
mand:
open typhoon.unl.edu
open 129.93.33.24
Both of these try to open the machine called typhoon at
the University of Nebraska. Using the symbolic name is
the preferred way, because IP addresses may change without
notice, while the symbolic names usually stay the same.
When you open a remote filesystem, you need to have per-
mission. The FTP Protocol's authentication system is very
similar to that of logging in to your account. You have
to give an account name, and its password for access to
that account's files. However, most remote systems that
have anything you might be interested in don't require an
account name for use. You can often get anonymous access
to a remote filesystem and exchange files that have been
made publicly accessible. The program attempts to get
anonymous permission to a remote system by default. What
actually happens is that the program tries to use ``anony-
mous'' as the account name, and when prompted for a pass-
word, uses your E-mail address as a courtesy to the remote
system's maintainer. You can have the program try to use
a specific account also. That will be explained later.
After the open command completes successfully, you are
connected to the remote system and logged in. You should
now see the command prompt change to reflect the name of
the current remote directory. To see what's in the cur-
rent remote directory, you can use the program's ls and
dir commands. The former is terse, preferring more remote
files in less screen space, and the latter is more ver-
bose, giving detailed information about each item in the
directory.
You can use the program's cd command to move to other
directories on the remote system. The cd command behaves
very much like the command of the same name in the Bourne
and Korn shell.
The purpose of the program is to exchange data with other
systems. You can use the program's get command to copy a
file from the remote system to your local system:
get README.txt
The program will display the progress of the transfer on
the screen, so you can tell how much needs to be done
before the transfer finishes. When the transfer does fin-
ish, then you can enter more commands to the program's
command shell.
You can use the program's put command to copy a file from
your system to the remote system:
put something.tar
When you are finished using the remote system, you can
open another one or use the quit
Before quitting, you may want to save the current FTP ses-
sion's settings for later. You can use the bookmark com-
mand to save an entry into your $HOME/.ncftp/bookmarks
file. When you use the bookmark command, you also specify
a bookmark name, so the next time instead of opening the
full hostname you can use the name of the bookmark. A
bookmark acts just like one for your web browser, so it
saves the remote directory you were in, the account name
you used, etc., and other information it learned so that
the next time you use the bookmark it should require as
little effort from you as possible.
COMMAND REFERENCE
help The first command to know is help. If you just
type
help
from the command shell, the program prints the
names of all of the supported commands. From
there, you can get specific help for a command by
typing the command after, for example:
help open
prints information about the open command.
ascii This command sets the transfer type to ASCII text.
This is useful for text-only transfers because the
concept of text files differs between operating
systems. For example on UNIX, a text file denotes
line breaks with the linefeed character, while on
MS-DOS a line break is denoted by both a carriage
return character and a line feed character. There-
fore, for data transfers that you consider the data
as text you can use ascii to ensure that both the
remote system and local system translate accord-
ingly. The default transfer type that ncftp uses
is not ASCII, but straight binary.
bgget and bgput
These commands correspond to the get and put com-
mands explained below, except that they do the job
in the background. Normally when you do a get then
the program does the download immediately, and does
not return control to you until the download com-
pletes. The background transfers are nice because
you can continue browsing the remote filesystem and
even open other systems. In fact, they are done by
a daemon process, so even if you log off your UNIX
host the daemon should still do your transfers.
And, it will automatically the continue to retry
the transfers until they finish. To tell when
background jobs have finished, you have to examine
the $HOME/.ncftp/batchlog file, or run the jobs
command from within NcFTP.
Both the bgget and bgput commands allow you to
schedule when to do the transfers. They take a
``-@'' parameter, whose argument is a date of the
form YYYYMMDDhhmmss (four digit year, month, day,
hour, minute, second). For example, to schedule a
download at 3 AM on November 6, you could try:
bgget -@ 19971106030000 /pub/idstuff/quake/q2_100.zip
bgstart
This command tells ncftp to immediately start the
background transfers you've requested, which simply
runs a copy of the ncftpbatch program which is
responsible for the background jobs. Normally the
program will start the background job as soon as
you close the current site, open a new site, or
quit the program. The reason for this is because
since so many users still use slow dialup links
that starting the transfers would slow things to a
crawl, making it difficult to browse the remote
system. An added bonus of starting the background
job when you close the site is that ncftp can pass
off that open connection to the ncftpbatch program.
That is nice when the site is always busy, so that
the background job doesn't have to wait and get re-
logged on to do its job.
binary Sets the transfer type to raw binary, so that no
translation is done on the data transferred. This
is the default anyway, since most files are in
binary.
bookmark
Saves the current session settings for later use.
This is useful to save the remote system and remote
working directory so you can quickly resume where
you left off some other time. The bookmark data is
stored in your $HOME/.ncftp/bookmarks file.
bookmarks
Lists the contents of your $HOME/.ncftp/bookmarks
file in a human-readable format. You can use this
command to recall the bookmark name of a previously
saved bookmark, so that you can use the open com-
mand with it.
cat Acts like the ``/bin/cat'' UNIX command, only for
remote files. This downloads the file you specify
and dumps it directly to the screen. You will
probably find the page command more useful, since
that lets you view the file one screen at a time
instead of printing the entire file at once.
cd Changes the working directory on the remote host.
Use this command to move to different areas on the
remote server. If you just opened a new site, you
might be in the root directory. Perhaps there was
a directory called ``/pub/news/comp.sources.d''
that someone told you about. From the root direc-
tory, you could:
cd pub
cd news
cd comp.sources.d
or, more concisely,
cd /pub/news/comp.sources.d
Then, commands such as get, put, and ls could be
used to refer to items in that directory.
Some shells in the UNIX environment have a feature
I like, which is switching to the previous direc-
tory. Like those shells, you can do:
cd -
to change to the last directory you were in.
chmod Acts like the ``/bin/chmod'' UNIX command, only for
remote files. However, this is not a standard com-
mand, so remote FTP servers may not support it.
close Disconnects you from the remote server. The pro-
gram does this for you automatically when needed,
so you can simply open other sites or quit the pro-
gram without worrying about closing the connection
by hand.
debug This command is mostly for internal testing. You
could type
debug 1
to turn debugging mode on. Then you could see all
messages between the program and the remote server,
and things that are only printed in debugging mode.
However, this information is also available in the
$HOME/.ncftp/trace file, which is created each time
you run ncftp. If you need to report a bug, send a
trace file if you can.
dir Prints a detailed directory listing. It tries to
behave like UNIX's ``/bin/ls -l'' command. If the
remote server seems to be a UNIX host, you can also
use the same flags you would with ls, for instance
dir -rt
would try to act like
/bin/ls -lrt
would on UNIX.
get Copies files from the current working directory on
the remote host to your machine's current working
directory. To place a copy of ``README'' and
``README.too'' in your local directory, you could
try:
get README README.too
You could also accomplish that by using a wildcard
expression, such as:
get README*
This command is similar to the behavior of other
FTP programs' mget command. To retrieve a remote
file but give it a different name on your host, you
can use the ``-z'' flag. This example shows how to
download a file called ReadMe.txt but name it
locally as README:
get -z ReadMe.txt README
The program tries to ``resume'' downloads by
default. This means that if the remote FTP server
lost the connection and was only able to send 490
kilobytes of a 500 kilobyte file, you could recon-
nect to the FTP server and do another get on the
same file name and it would get the last 10 kilo-
bytes, instead of retrieving the entire file again.
There are some occasions where you may not want
that behavior. To turn it off you can use the
``-Z'' flag.
There are also times where you want to append to an
existing file. You can do this by using the ``-A''
flag, for example
get -A log.11
would append to a file named ``log.11'' if it
existed locally.
Another thing you can do is delete a remote file
after you download it. This can be useful when a
remote host expects a file to be removed when it
has been retrieved. Use the double-D flag, such as
``get -DD'' to do this.
The get command lets you retrieve entire directory
trees, too. Although it may not work with some
remote systems, you can try ``get -R'' with a
directory to download the directory and its con-
tents.
jobs Views the list of currently executing NcFTP back-
ground tasks. This actually just runs ncftpbatch
-l for you.
lcd The lcd command is the first of a few ``l'' com-
mands that work with the local host. This changes
the current working directory on the local host.
If you want to download files into a different
local directory, you could use lcd to change to
that directory and then do your downloads.
lchmod Runs ``/bin/chmod'' on the local host.
lls Another local command that comes in handy is the
lls command, which runs ``/bin/ls'' on the local
host and displays the results in the program's win-
dow. You can use the same flags with lls as you
would in your command shell, so you can do things
like:
lcd ~/doc
lls -lrt p*.txt
lmkdir Runs ``/bin/mkdir'' on the local host.
lookup The program also has a built-in interface to the
name service via the lookup command. This means
you can lookup entries for remote hosts, like:
lookup cse.unl.edu ftp.cs.unl.edu sphygmomanometer.unl.edu
prints:
cse.unl.edu 129.93.33.1
typhoon.unl.edu 129.93.33.24
sphygmomanometer.unl.edu 129.93.33.126
There is also a more detailed option, enabled with
``-v,'' i.e.:
lookup -v cse.unl.edu ftp.cs.unl.edu
prints:
cse.unl.edu:
Name: cse.unl.edu
Address: 129.93.33.1
ftp.cs.unl.edu:
Name: typhoon.unl.edu
Alias: ftp.cs.unl.edu
Address: 129.93.33.24
You can also give IP addresses, so this would work
too:
lookup 129.93.33.24
prints:
typhoon.unl.edu 129.93.33.24
lpage Views a local file one page at a time, with your
preferred $PAGER program.
lpwd Prints the current local directory. Use this com-
mand when you forget where you are on your local
machine.
lrename
Runs ``/bin/mv'' on the local host.
lrm Runs ``/bin/rm'' on the local host.
lrmdir Runs ``/bin/rmdir'' on the local host.
ls Prints a directory listing from the remote system.
It tries to behave like UNIX's ``/bin/ls -CF'' com-
mand. If the remote server seems to be a UNIX
host, you can also use the same flags you would
with ls, for instance
ls -rt
would try to act like
/bin/ls -CFrt
would on UNIX.
ncftp has a powerful built-in system for dealing
with directory listings. It tries to cache each
one, so if you list the same directory, odds are it
will display instantly. Behind the scenes, ncftp
always tries a long listing, and then reformats it
as it needs to. So even if your first listing of a
directory was a regular ``ls'' which displayed the
files in columns, your next listing could be
``ls -lrt'' and ncftp would still use the cached
directory listing to quickly display the informa-
tion for you!
mkdir Creates a new directory on the remote host. For
many public archives, you won't have the proper
access permissions to do that.
open Establishes an FTP control connection to a remote
host. By default, ncftp logs in anonymously to the
remote host. You may want to use a specific user
account when you log in, so you can use the ``-u''
flag to specify which user. This example shows how
to open the host ``bowser.nintendo.co.jp'' using
the username ``mario:''
open -u mario bowser.nintendo.co.jp
page Browses a remote file one page at a time, using
your $PAGER program. This is useful for reading
README's on the remote host without downloading
them first.
pdir and pls
These commands are equivalent to dir and ls respec-
tively, only they feed their output to your pager.
These commands are useful if the directory listing
scrolls off your screen.
put Copies files from the local host to the remote
machine's current working directory. To place a
copy of ``xx.zip'' and ``yy.zip'' in the remote
directory, you could try:
put xx.zip yy.zip
You could also accomplish that by using a wildcard
expression, such as:
put *.zip
This command is similar to the behavior of other
FTP programs' mput command. To send a remote file
but give it a different name on your host, you can
use the ``-z'' flag. This example shows how to
upload a file called ``ncftpd-2.0.6.tar.gz'' but
name it remotely as ``NFTPD206.TGZ:''
put -z ncftpd-2.0.6.tar.gz NFTPD206.TGZ
The program does not try to ``resume'' uploads by
default. If you do want to resume an upload, use
the ``-z'' flag.
There are also times where you want to append to an
existing remote file. You can do this by using the
``-A'' flag, for example
put -A log11.txt
would append to a file named ``log11.txt'' if it
existed on the remote server.
Another thing you can do is delete a local file
after you upload it. Use the double-D flag, such
as ``put -DD'' to do this.
The put command lets you send entire directory
trees, too. It should work on all remote systems,
so you can try ``put -R'' with a directory to
upload the directory and its contents.
pwd Prints the current remote working directory. A
portion of the pathname is also displayed in the
shell's prompt.
quit Of course, when you finish using the program, type
quit to end the program (You could also use bye,
exit, or ^D).
quote This can be used to send a direct FTP Protocol com-
mand to the remote server. Generally this isn't
too useful to the average user.
rename If you need to change the name of a remote file,
you can use the rename command, like:
rename SPHYGMTR.TAR sphygmomanometer-2.3.1.tar
rhelp Sends a help request to the remote server. The
list of FTP Protocol commands is often printed, and
sometimes some other information that is actually
useful, like how to reach the site administrator.
Depending on the remote server, you may be able to
give a parameter to the server also, like:
rhelp NLST
One server responded:
Syntax: NLST [ <sp> path-name ]
rm If you need to delete a remote file you can try the
rm command. Much of the time this won't work
because you won't have the proper access permis-
sions. This command doesn't accept any flags, so
you can't nuke a whole tree by using ``-rf'' flags
like you can on UNIX.
rmdir Similarly, the rmdir command removes a directory.
Depending on the remote server, you may be able to
remove a non-empty directory, so be careful.
set This lets you configure some program variables,
which are saved between runs in the
$HOME/.ncftp/prefs file. The basic syntax is:
set <option> <value>
For example, to change the value you use for the
anonymous password, you might do:
set anon-password ncftp@ncftp.com
See the next section for a list of things you
change.
show This lets you display program variables. You can
do ``show all'' to display all of them, or give a
variable name to just display that one, such as:
show anon-password
site One obscure command you may have to use someday is
site. The FTP Protocol allows for ``site spe-
cific'' commands. These ``site'' commands vary of
course, such as:
site chmod 644 README
Actually, ncftp's chmod command really does the
above.
Try doing one of these to see what the remote
server supports, if any:
rhelp SITE
site help
type You may need to change transfer types during the
course of a session with a server. You can use the
type command to do this. Try one of these:
type ascii
type binary
type image
The ascii command is equivalent to ``type a'', and
the binary command is equivalent to ``type i'' and
``type b''.
umask Sets the process' umask on the remote server, if it
has any concept of a umask, i.e.:
umask 077
However, this is not a standard command, so remote
FTP servers may not support it.
version
This command dumps some information about the par-
ticular edition of the program you are using, and
how it was installed on your system.
VARIABLE REFERENCE
anon-password
Specifies what to use for the password when logging
in anonymously. Internet convention has been to
use your E-mail address as a courtesy to the site
administrator. If you change this, be aware that
some sites require (i.e. they check for) valid E-
mail addresses.
confirm-close
By default the program will ask you when a site you
haven't bookmarked is about to be closed. To turn
this prompt off, you can set this variable to no.
connect-timeout
Previous versions of the program used a single
timeout value for everything. You can now have
different values for different operations. How-
ever, you probably do not need to change these from
the defaults unless you have special requirements.
The connect-timeout variable controls how long to
wait, in seconds, for a connection establishment to
complete before considering it hopeless. You can
choose to not use a timeout at all by setting this
to -1.
control-timeout
This is the timer used when ncftp sends an FTP com-
mand over the control connection to the remote
server. If the server hasn't replied in that many
seconds, it considers the session lost.
pager This is the external program to use to view a text
file, and is more by default.
passive
This controls ncftp's behavior for data connec-
tions, and can be set to one of on, off, or the
default, optional. When passive mode is on, ncftp
uses the FTP command primitive PASV to have the
client establish data connections to the server.
The default FTP protocol behavior is to use the FTP
command primitive PORT which has the server estab-
lish data connections to the client. The default
setting for this variable, optional, allows ncftp
to choose whichever method it deems necessary.
progress-meter
You can change how the program reports file trans-
fer status. Select from meter 2, 1, or 0.
save-passwords
If you set this variable to yes, the program will
save passwords along with the bookmarks you save.
While this makes non-anonymous logins more conve-
nient, this can be very dangerous since your
account information is now sitting in the
$HOME/.ncftp/bookmarks file. The passwords aren't
in clear text, but it is still trivial to decode
them if someone wants to make a modest effort.
xfer-timeout
This timer controls how long to wait for data
blocks to complete. Don't set this too low or else
your transfers will timeout without completing.
FIREWALL AND PROXY CONFIGURATION
You may find that your network administrator has placed a
firewall between your machine and the Internet, and that
you cannot reach external hosts.
The answer may be as simple as setting ncftp to use pas-
sive mode only, which you can do from a ncftp command
prompt like this:
set passive yes
The reason for this is because many firewalls do not allow
incoming connections to the site, but do allow users to
establish outgoing connections. A passive data connection
is established by the client to the server, whereas the
default is for the server to establish the connection to
the client, which firewalls may object to. Of course, you
now may have problems with sites whose primitive FTP
servers do not support passive mode.
Otherwise, if you know you need to have ncftp communicate
directly with a firewall or proxy, you can try editing the
separate $HOME/.ncftp/firewall configuration file. This
file is created automatically the first time you run the
program, and contains all the information you need to get
the program to work in this setup.
The basics of this process are configuring a firewall
(proxy) host to go through, a user account and password
for authentication on the firewall, and which type of
firewall method to use. You can also setup an exclusion
list, so that ncftp does not use the firewall for hosts on
the local network.
FILES
$HOME/.ncftp/batchlog
Information for background data transfer processes.
$HOME/.ncftp/bookmarks
Saves bookmark and host information.
$HOME/.ncftp/firewall
Firewall access configuration file.
$HOME/.ncftp/prefs
Program preferences.
$HOME/.ncftp/spool/
Directory where background jobs are stored in the
form of spool configuration files.
$HOME/.ncftp/trace
Debugging output for entire program run.
$HOME/.ncftp/v3init
Used to tell if this version of the program has run
before.
ENVIRONMENT
PATH User's search path, used to find the ncftpbatch
program, pager, and some other system utilities.
PAGER Program to use to view text files one page at a
time.
TERM If the program was compiled with support for GNU
Readline it will need to know how to manipulate the
terminal correctly for line-editing, etc. The
pager program will also take advantage of this set-
ting.
HOME By default, the program writes its configuration
data in a .ncftp subdirectory of the HOME direc-
tory.
NCFTPDIR
If set, the program will use this directory instead
of $HOME/.ncftp. This variable is optional except
for those users whose home directory is the root
directory.
COLUMNS
Both the built-in ls command and the external ls
command need this to determine how many screen
columns the terminal has.
BUGS
There are no such sites named bowser.nintendo.co.jp or
sphygmomanometer.unl.edu.
Auto-resume should check the file timestamps instead of
relying upon just the file sizes, but it is difficult to
do this reliably within FTP.
Directory caching and recursive downloads depend on
UNIX-like behavior of the remote host.
AUTHOR
Mike Gleason, NCEMRSoft (mgleason@ncftp.com).
SEE ALSO
ncftpput(1), ncftpget(1), ncftpbatch(1), ftp(1), rcp(1),
tftp(1).
LibNcFTP (http://www.ncftp.com/libncftp).
NcFTPd (http://www.ncftp.com/ncftpd).
THANKS
Thanks to everyone who uses the program. Your support is
what drives me to improve the program!
I thank Dale Botkin and Tim Russell at my former ISP,
Probe Technology.
Ideas and some code contributed by my partner, Phil Dietz.
Thanks to Brad Mittelstedt and Chris Tjon, for driving and
refining the development of the backbone of this project,
LibNcFTP.
I'd like to thank my former system administrators, most
notably Charles Daniel, for making testing on a variety of
platforms possible, letting me have some extra disk space,
and for maintaining the UNL FTP site.
For testing versions 1 and 2 above and beyond the call of
duty, I am especially grateful to: Phil Dietz,
Kok Hon Yin, and Andrey A. Chernov (ache@astral.msk.su).
Thanks to Tim MacKenzie (t.mackenzie@trl.oz.au) for the
original filename completion code for version 2.3.0 and
2.4.2.
Thanks to DaviD W. Sanderson (dws@ora.com.), for helping
me out with the man page.
Thanks to those of you at UNL who appreciate my work.
Thanks to RedHat Software for honoring my licensing agree-
ment, but more importantly, thanks for providing a solid
and affordable development platform.
APOLOGIES
To the users, for not being able to respond personally to
most of your inquiries.
To Phil, for things not being the way they should be.
NCEMRSoft 1
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