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File Transfer Across The Internet With ftp

Promiscuous Ftp connections are allowed out, but not in to MSRI. To ftp files into MSRI from a remote site you must use S/KEY for authentication.

If you do not already have an account at MSRI, you may ftp to ftp.msri.org and login as ftp. You can then put your files in /incoming, and a member of the computing staff will help you retrieve them upon your arrival.

Note:Unfortunately, the ftp client for the Macintosh, Fetch was developed by NCSA, and both NCSA and Apple began loosing their best Internet programmers about the time that firewalls became wide-spread. Consequently, Fetch doesn't understand firewalls, and it is impossible to use fetch to transfer files between MSRI and the outside world.

One work-around is to use Netscape on the Macs. If the remote site is serving both ftp and http (World-Wide Web), you can use Netscape to open a URL like ftp://ftp.msri.org, for example, in order to retrieve files from the anonymous ftp archive here at MSRI. Another is to use ftp under Unix between MSRI and the Internet, and use Fetch between a MSRI Mac and a MSRI Unix machine.

Copying Just a Few Files

1. Login to your MSRI account
2. Start the ftp program by typing:ftp remoteSite. You will then be prompted for a login ( your own at the remote site, or ftp, if you don't have one and are using ftp anonymously) and password ( your own at the remote site, or yourMSRIloginID@msri.org, if you don't have one and are using ftp anonymously).
3. Copy the file(s)

The ftp program is interactive; it presents you with a ftp> prompt, and waits for you to type commands.

For historical reasons, ftp wakes up in text mode which will garble any non-text file, as well as many non-English text files; to guard against this, issue the command ftp> binary to toggle ftp into so-called Image mode.

Since I am an impatient person, I also like to tell it ftp> hash so that it will print out hash marks as the file transfer progresses.

Ftp's two most basic commands are
ftp> put filename
and
ftp> get filename
for receiving and sending files respectively.

You can navigate within file systems using the ftp commands
ftp> lcd some/where
locally and
ftp> cd somewhere/else/remote
remotely to change directories.

Within ftp the command
ftp> ls
will list remote files.

There are also commands
ftp> mget regularExpression
and
ftp> mput regularExpression
which allow you to use wildcards to retrieve or send all files matching regularExpression. For example,
ftp> mget *.tex
will query you if you wish to retrieve each file whose names end in .tex. If you are confident about your regular expression, you can suppress the prompting before you begin with the prompt toggle in ftp.

Control-C aborts ftp commands, and
ftp> bye
exits ftp.

Here is a complete example:

myPrompt% ftp godel.geom.umn.edu
Connected to godel.geom.umn.edu.
220 godel FTP server (SunOS 4.1) ready.
Name (godel.geom.umn.edu:joe): joe
331 Password required for joe.
Password:
230 User joe logged in.
ftp> hash
Hash mark printing on (8192 bytes/hash mark).
ftp> binary
200 Type set to I.
ftp> ls
200 PORT command successful.
150 Opening ASCII mode data connection for file list.
foo
bar
baz
bash_defaults
226 Transfer complete.
547 bytes received in 0.18 seconds (2.9 Kbytes/s)
ftp> get foo
200 PORT command successful.
150 Opening BINARY mode data connection for foo (13 bytes).
#
226 Transfer complete.
local: foo remote: foo
13 bytes received in 0.02 seconds (0.64 Kbytes/s)
ftp> mget b*
mget bar? y
200 PORT command successful.
150 Opening BINARY mode data connection for bar (12 bytes).
#
226 Transfer complete.
local: bar remote: bar
12 bytes received in 0.018 seconds (0.65 Kbytes/s)
mget bash_defaults/.bash_alias? n
mget bash_defaults/.bash_login? n
mget bash_defaults/.bashrc? n
mget baz? y
200 PORT command successful.
150 Opening BINARY mode data connection for baz (13 bytes).
#
226 Transfer complete.
local: baz remote: baz
13 bytes received in 0.017 seconds (0.77 Kbytes/s)
ftp> bye

Copying Entire Directory Trees

Overview

1. Login to your MSRI account.
2. Create a tar archive.
3. Compress the tar archive.
4. Transfer the compressed tar archive with ftp.
5. Uncompress the tar archive.
6. Un-archive the tar archive.

We will use the UNIX utility tar to ``roll up'' an entire directory tree into a single file. We'll then transfer that file via ftp, and reverse the tar process at the other end. Be aware that tar archives can be quite large - as large as the directory tree you're moving. If you're trying to copy a 5M directory, but you have a 3M quota at the remote site, your tar file won't fit!

Using tar

Tar (for Tape Archive and Restore) was originally written to do tape backups. Since then it has been superseded for backups, but it remains the best tool for condensing sprawling masses of files into a single, easily handled file.

Tar has three basic modes, create - flag c, extract - flag x, list - flag t, for creating, extracting and listing the contents of an archive. Tar has many other flags (see the tar man page), but only one need concern us here: f, for file. The mode flags must come first, and, since it takes a filename as an argument, the f flag should come last. In create mode, tar itself takes as an argument a list of the directories and files that you wish to archive. By convention, tar archives have the extension .tar.

For example,

tar -cf foo.tar bar baz

tar -cf texFiles.tar *.tex

We can remind ourselves of the contents of the archive foo.tar using list mode:

tar -tf foo.tar

bar
baz/
baz/quux

yourPrompt% tar -tvf foo.tar
-rw-r--r-- joe/wheel        13 Sep  5 16:01 1994 bar
drwxr-xr-x joe/wheel         0 Sep  5 16:01 1994 baz/
-rw-r--r-- joe/wheel        14 Sep  5 16:01 1994 baz/quux

tar -xf texFiles.tar

Using compress

To save space, there is the compress command. It comes in two flavors, compress and uncompress, the use of which is pretty straightforward:

compress texFiles.tar

uncompress texFiles.tar.Z

A Superior Alternative

Many, but, alas, not all, sites support the completely analogous and vastly superior GNU utilities gzip and gunzip for compressing and uncompressing files. While gzip can read .Z files, it creates (smaller) files with the extension .gz. Moreover, the GNU version of tar, sometimes called gnutar, understands the .gz file format, and when given the z flag, can combine gzip compression and decompression with tar archive creation and extraction.

Thus, with GNU tar, the single command

tar -czf texFiles.tar.gz *.tex

tar -cf texFiles.tar *.tex; compress texFiles.tar

tar -xzf texFiles.tar.gz

uncompress texFiles.tar.Z; tar -xf texFiles.tar

Authenticated ftp into MSRI

In more detail, first ftp to the firewall machine, msri.org.

Next, generate a one-time password in response on your local machine.

Once authenticated, at the MSRI> prompt on the firewall, type user username@machinename, where username is the name of your MSRI account, and machinename is the name of some machine at MSRI, e.g. the one on your desk.

respond with your MSRI password, and proceed as before.

Transferring Files Among DOS/Windows, Mac, and UNIX

With any of these methods you may encounter a problem with line terminators. The symptoms are either unwanted control characters in your file, visible as ^M and the like, or the appearance that your file is all one terribly long line. To cope with these problems, use the UNIX commands mac2unix, unix2mac, dos2unix, and unix2dos which translate line terminators.

Using DOS diskettes in a Linux PC

mdir A:

list the contents of the diskette

mcopy file A:

copy file to the diskette

mcopy A:file.ext .

copy file.ext from the diskette

mdel A:file.ext

delete file from the diskette

eject

eject the diskette

File Transfer Between Macs and UNIX, using a Mac

• Sit down at a Macintosh;
• Launch the Fetch application by double-clicking on its icon;
• In the Open Connection window enter your username, password, and /u/username;
• Select and transfer the files.

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