[u/mdw/putty] / doc / psftp.but

\versionid $Id: psftp.but,v 1.2 2001/12/14 12:22:09 simon Exp $

\C{psftp} Using PSFTP to transfer files securely

\i{PSFTP}, the PuTTY SFTP client, is a tool for transferring files
securely between computers using an SSH connection.

PSFTP differs from PSCP in the following ways:

\b PSCP should work on virtually every SSH server. PSFTP uses the
new SFTP protocol, which is a feature of SSH 2 only. (PSCP will also
use this protocol if it can, but there is an SSH 1 equivalent it can
fall back to if it cannot.)

\b PSFTP allows you to run an interactive file transfer session,
much like the Windows \c{ftp} program. You can list the contents of
directories, browse around the file system, issue multiple \c{get}
and \c{put} commands, and eventually log out. By contrast, PSCP is
designed to do a single file transfer operation and immediately
terminate.

\H{psftp-starting} Starting PSFTP

The usual way to start PSFTP is from a command prompt, much like
PSCP. To do this, it will need either to be on your \i{\c{PATH}} or
in your current directory.  To add the directory containing PSFTP to
your \c{PATH} environment variable, type into the console window:

\c set PATH=C:\path\to\putty\directory;%PATH%

Unlike PSCP, however, PSFTP has no complex command-line syntax; you
just specify a host name and perhaps a user name:

\c psftp server.example.com

or perhaps

\c psftp fred@server.example.com

Alternatively, if you just type \c{psftp} on its own (or
double-click the PSFTP icon in the Windows GUI), you will see the
PSFTP prompt, and a message telling you PSFTP has not connected to
any server:

\c C:\>psftp
\c psftp: no hostname specified; use "open host.name" to connect
\c psftp>

At this point you can type \c{open server.example.com} or \c{open
fred@server.example.com} to start a session.

The following sections describe PSFTP's command-line options.

\S{psftp-option-l} \c{-l}: specify a user name

The \c{-l} option is an alternative way to specify the user name to
log in as, on the command line. Instead of typing \c{psftp
user@host}, you can also type \c{psftp host -l user}.

This option does not work in the \c{open} command once PSFTP has
started.

\S{psftp-option-P} \c{-P}: specify a port number

If the \c{host} you specify is a saved session, PSFTP uses any port
number specified in that saved session.  If not, PSFTP uses the
default SSH port, 22.  The \c{-P} option allows you specify the port
number to connect to for PSFTP's SSH connection.

\S{psftp-option-v}\c{-v}: show verbose messages

The \c{-v} option to PSFTP makes it print verbose information about
the establishing of the SSH connection. The information displayed is
equivalent to what is shown in the PuTTY Event Log
(\k{using-eventlog}).

This information may be useful for debugging problems with PSFTP.

\S{psftp-option-pw} \c{-pw}: specify a password

If a password is required to connect to the \c{host}, PSFTP will
interactively prompt you for it.  However, this may not always be
appropriate.  If you are running PSFTP as part of some automated
job, it will not be possible to enter a password by hand.  The
\c{-pw} option to PSFTP lets you specify the password to use on the
command line.

Since specifying passwords in scripts is a bad idea for security
reasons, you might want instead to consider using public-key
authentication; see \k{psftp-pubkey}.

\S{psftp-option-b} \c{-b}: specify a file containing batch commands

In normal operation, PSFTP is an interactive program which displays
a command line and accepts commands from the keyboard.

If you need to do automated tasks with PSFTP, you would probably
prefer to specify a set of commands in advance and have them
executed automatically. The \c{-b} option allows you to do this. You
use it with a file name containing batch commands. For example, you
might create a file called \c{myscript.scr} containing lines like
this:

\c cd /home/ftp/users/jeff
\c del jam-old.tar.gz
\c ren jam.tar.gz jam-old.tar.gz
\c put jam.tar.gz
\c chmod a+r jam.tar.gz
\c quit

and then you could run the script by typing

\c psftp user@hostname -b myscript.scr

When you run a batch script in this way, PSFTP will abort the script
if any command fails to complete successfully. To change this
behaviour, you can use the \c{-be} option (\k{psftp-option-be}).

\S{psftp-option-bc} \c{-bc}: display batch commands as they are run

The \c{-bc} option alters what PSFTP displays while processing a
batch script. With the \c{-bc} option, PSFTP will display prompts
and commands just as if the commands had been typed at the keyboard.
So instead of seeing this:

\c Sent username "fred"
\c Remote working directory is /home/fred
\c Listing directory /home/fred/lib
\c drwxrwsr-x    4 fred     fred         1024 Sep  6 10:42 .
\c drwxr-sr-x   25 fred     fred         2048 Dec 14 09:36 ..
\c drwxrwsr-x    3 fred     fred         1024 Apr 17  2000 jed
\c lrwxrwxrwx    1 fred     fred           24 Apr 17  2000 timber
\c drwxrwsr-x    2 fred     fred         1024 Mar 13  2000 trn

you might see this:

\c Sent username "fred"
\c Remote working directory is /home/fred
\c psftp> dir lib
\c Listing directory /home/fred/lib
\c drwxrwsr-x    4 fred     fred         1024 Sep  6 10:42 .
\c drwxr-sr-x   25 fred     fred         2048 Dec 14 09:36 ..
\c drwxrwsr-x    3 fred     fred         1024 Apr 17  2000 jed
\c lrwxrwxrwx    1 fred     fred           24 Apr 17  2000 timber
\c drwxrwsr-x    2 fred     fred         1024 Mar 13  2000 trn
\c psftp> quit

\S{psftp-option-be} \c{-be}: continue batch processing on errors

When running a batch file, this option causes PSFTP to continue
processing even if a command fails to complete successfully.

You might want this to happen if you wanted to delete a file and
didn't care if it was already not present, for example.

\H{psftp-commands} Running PSFTP

Once you have started your PSFTP session, you will see a \c{psftp>}
prompt. You can now type commands to perform file-transfer
functions. This section lists all the available commands.

\S{psftp-cmd-open} The \c{open} command: start a session

If you started PSFTP by double-clicking in the GUI, or just by
typing \c{psftp} at the command line, you will need to open a
connection to an SFTP server before you can issue any other
commands (except \c{help} and \c{quit}).

To create a connection, type \c{open host.name}, or if you need to
specify a user name as well you can type \c{open user@host.name}.

Once you have issued this command, you will not be able to issue it
again, \e{even} if the command fails (for example, if you mistype
the host name or the connection times out). So if the connection is
not opened successfully, PSFTP will terminate immediately.

\S{psftp-cmd-quit} The \c{quit} command: end your session

When you have finished your session, type the command \c{quit} to
terminate PSFTP and return to the command line (or just close the
PSFTP console window if you started it from the GUI).

You can also use the \c{bye} and \c{exit} commands, which have
exactly the same effect.

\S{psftp-cmd-help} The \c{help} command: get quick online help

If you type \c{help}, PSFTP will give a short list of the available
commands.

If you type \c{help} with a command name - for example, \c{help get}
- then PSFTP will give a short piece of help on that particular
command.

\S{psftp-cmd-cd} The \c{cd} and \c{pwd} commands: changing the
remote working directory

PSFTP maintains a notion of your \q{working directory} on the
server. This is the default directory that other commands will
operate on. For example, if you type \c{get filename.dat} then PSFTP
will look for \c{filename.dat} in your working directory on the
server.

To change your working directory, use the \c{cd} command. To display
your current working directory, type \c{pwd}.

\S{psftp-cmd-get} The \c{get} command: fetch a file from the server

To download a file from the server and store it on your local PC,
you use the \c{get} command.

In its simplest form, you just use this with a file name:

\c get myfile.dat

If you want to store the file locally under a different name,
specify the local file name after the remote one:

\c get myfile.dat newname.dat

This will fetch the file on the server called \c{myfile.dat}, but
will save it to your local machine under the name \c{newname.dat}.

\S{psftp-cmd-put} The \c{put} command: send a file to the server

To upload a file to the server from your local PC, you use the
\c{put} command.

In its simplest form, you just use this with a file name:

\c put myfile.dat

If you want to store the file remotely under a different name,
specify the remote file name after the local one:

\c put myfile.dat newname.dat

This will send the local file called \c{myfile.dat}, but will store
it on the server under the name \c{newname.dat}.

\S{psftp-cmd-regetput} The \c{reget} and \c{reput} commands:
resuming file transfers

If a file transfer fails half way through, and you end up with half
the file stored on your disk, you can resume the file transfer using
the \c{reget} and \c{reput} commands. These work exactly like the
\c{get} and \c{put} commands, but they check for the presence of the
half-written destination file and start transferring from where the
last attempt left off.

The syntax of \c{reget} and \c{reput} is exactly the same as the
syntax of \c{get} and \c{put}:

\c reget myfile.dat
\c reget myfile.dat newname.dat

\S{psftp-cmd-dir} The \c{dir} command: list remote files

To list the files in your remote working directory, just type
\c{dir}.

You can also list the contents of a different directory by typing
\c{dir} followed by the directory name:

\c dir /home/fred
\c dir sources

The \c{ls} command works exactly the same way as \c{dir}.

\S{psftp-cmd-chmod} The \c{chmod} command: change permissions on
remote files

PSFTP allows you to modify the file permissions on files on the
server. You do this using the \c{chmod} command, which works very
much like the Unix \c{chmod} command.

The basic syntax is \c{chmod modes file}, where \c{modes} represents
a modification to the file permissions, and \c{file} is the filename
to modify. For example:

\c chmod go-rwx,u+w privatefile
\c chmod a+r publicfile
\c chmod 640 groupfile

The \c{modes} parameter can be a set of octal digits in the Unix
style. (If you don't know what this means, you probably don't want
to be using it!) Alternatively, it can be a list of permission
modifications, separated by commas. Each modification consists of:

\b The people affected by the modification. This can be \c{u} (the
owning user), \c{g} (members of the owning group), or \c{o}
(everybody else - \q{others}), or some combination of those. It can
also be \c{a} (\q{all}) to affect everybody at once.

\b A \c{+} or \c{-} sign, indicating whether permissions are to be
added or removed.

\b The actual permissions being added or removed. These can be \c{r}
(permission to read the file), \c{w} (permission to write to the
file), and \c{x} (permission to execute the file, or in the case of
a directory, permission to access files within the directory).

So the above examples would do:

\b The first example: \c{go-rwx} removes read, write and execute
permissions for members of the owning group and everybody else (so
the only permissions left are the ones for the file owner). \c{u+w}
adds write permission for the file owner.

\b The second example: \c{a+r} adds read permission for everybody.

In addition to all this, there are a few extra special cases for
Unix systems. On non-Unix systems these are unlikely to be useful:

\b You can specify \c{u+s} and \c{u-s} to add or remove the Unix
set-user-ID bit. This is typically only useful for special purposes;
refer to your Unix documentation if you're not sure about it.

\b You can specify \c{g+s} and \c{g-s} to add or remove the Unix
set-group-ID bit. On a file, this works similarly to the set-user-ID
bit (see your Unix documentation again); on a directory it ensures
that files created in the directory are accessible by members of the
group that owns the directory.

\b You can specify \c{+t} and \c{-t} to add or remove the Unix
\q{sticky bit}. When applied to a directory, this means that the
owner of a file in that directory can delete the file (whereas
normally only the owner of the \e{directory} would be allowed to).

\S{psftp-cmd-del} The \c{del} command: delete remote files

To delete a file on the server, type \c{del} and then the filename:

\c del oldfile.dat

The \c{rm} command works exactly the same way as \c{del}.

\S{psftp-cmd-mkdir} The \c{mkdir} command: create remote directories

To create a directory on the server, type \c{mkdir} and then the
directory name:

\c mkdir newstuff

\S{psftp-cmd-rmdir} The \c{rmdir} command: remove remote directories

To remove a directory on the server, type \c{rmdir} and then the
directory name:

\c rmdir oldstuff

Most SFTP servers will probably refuse to remove a directory if the
directory has anything in it, so you will need to delete the
contents first.

\S{psftp-cmd-ren} The \c{ren} command: rename remote files

To rename a file on the server, type \c{ren}, then the current file
name, and then the new file name:

\c ren oldfile newname

The \c{rename} and \c{mv} commands work exactly the same way as
\c{ren}.

\H{psftp-pubkey} Using public key authentication with PSFTP

Like PuTTY, PSFTP can authenticate using a public key instead of a
password. There are two ways you can do this.

Firstly, PSFTP can use PuTTY saved sessions in place of hostnames.
So you might do this:

\b Run PuTTY, and create a PuTTY saved session (see
\k{config-saving}) which specifies your private key file (see
\k{config-ssh-privkey}). You will probably also want to specify a
username to log in as (see \k{config-username}).

\b In PSFTP, you can now use the name of the session instead of a
hostname: type \c{psftp sessionname}, where \c{sessionname} is
replaced by the name of your saved session.

Secondly, PSFTP will attempt to authenticate using Pageant if Pageant
is running (see \k{pageant}). So you would do this:

\b Ensure Pageant is running, and has your private key stored in it.

\b Specify a user and host name to PSFTP as normal. PSFTP will
automatically detect Pageant and try to use the keys within it.

For more general information on public-key authentication, see
\k{pubkey}.