zshzftpsys - zftp function front-end
This describes the set of shell functions supplied with the source distribution as an interface to the zftp builtin command, allowing you to perform FTP operations from the shell command line or within functions or scripts. The interface is similar to a traditional FTP client (e.g. the ftp command itself, see ftp(1)), but as it is entirely done within the shell all the familiar completion, editing and globbing features, and so on, are present, and macros are particularly simple to write as they are just ordinary shell functions.
The prerequisite is that the zftp command, as described in zshmodules(1) , must be available in the version of zsh installed at your site. If the shell is configured to load new commands at run time, it probably is: typing `zmodload zsh/zftp' will make sure (if that runs silently, it has worked). If this is not the case, it is possible zftp was linked into the shell anyway: to test this, type `which zftp' and if zftp is available you will get the message `zftp: shell built-in command'.
Commands given directly with zftp builtin may be interspersed between the functions in this suite; in a few cases, using zftp directly may cause some of the status information stored in shell parameters to become invalid. Note in particular the description of the variables $ZFTP_TMOUT, $ZFTP_PREFS and $ZFTP_VERBOSE for zftp.
You should make sure all the functions from the Functions/Zftp directory of the source distribution are available; they all begin with the two letters `zf'. They may already have been installed on your system; otherwise, you will need to find them and copy them. The directory should appear as one of the elements of the $fpath array (this should already be the case if they were installed), and at least the function zfinit should be autoloaded; it will autoload the rest. Finally, to initialize the use of the system you need to call the zfinit function. The following code in your .zshrc will arrange for this; assume the functions are stored in the directory ~/myfns:
fpath=(~/myfns $fpath) autoload -U zfinit zfinit
Note that zfinit assumes you are using the zmodload method to load the zftp command. If it is already built into the shell, change zfinit to zfinit -n. It is helpful (though not essential) if the call to zfinit appears after any code to initialize the new completion system, else unnecessary compctl commands will be given.
The sequence of operations in performing a file transfer is essentially the same as that in a standard FTP client. Note that, due to a quirk of the shell's getopts builtin, for those functions that handle options you must use `--' rather than `-' to ensure the remaining arguments are treated literally (a single `-' is treated as an argument).
A single argument `-' will delete the stored parameters. This will also cause the memory of the last directory (and so on) on the other host to be deleted.
If the command was successful, and the terminal is compatible with xterm or is sun-cmd, a summary will appear in the title bar, giving the local host:directory and the remote host:directory; this is handled by the function zftp_chpwd, described below.
Normally, the host, user and password are internally recorded for later re-opening, either by a zfopen with no arguments, or automatically (see below). With the option `-1', no information is stored. Also, if an open command with arguments failed, the parameters will not be retained (and any previous parameters will also be deleted). A zfopen on its own, or a zfopen -1, never alters the stored parameters.
Both zfopen and zfanon (but not zfparams) understand URLs of the form ftp://host/path... as meaning to connect to the host, then change directory to path (which must be a directory, not a file). The `ftp://' can be omitted; the trailing `/' is enough to trigger recognition of the path. Note prefixes other than `ftp:' are not recognized, and that all characters after the first slash beyond host are significant in path.
In the first form with dir present, change to the directory dir. The command `zfcd ..' is treated specially, so is guaranteed to work on non-UNIX servers (note this is handled internally by zftp). If dir is omitted, has the effect of `zfcd ~'.
The second form changes to the directory previously current.
The third form attempts to change the current directory by replacing the first occurrence of the string old with the string new in the current directory.
Note that in this command, and indeed anywhere a remote filename is expected, the string which on the local host corresponds to `~' is converted back to a `~' before being passed to the remote machine. This is convenient because of the way expansion is performed on the command line before zfcd receives a string. For example, suppose the command is `zfcd ~/foo'. The shell will expand this to a full path such as `zfcd /home/user2/pws/foo'. At this stage, zfcd recognises the initial path as corresponding to `~' and will send the directory to the remote host as ~/foo, so that the `~' will be expanded by the server to the correct remote host directory. Other named directories of the form `~name' are not treated in this fashion.
The directory is usually cached for re-use. In fact, two caches are maintained. One is for use when there is no dir-options or dir, i.e. a full listing of the current remote directory; it is flushed when the current remote directory changes. The other is kept for repeated use of zfdir with the same arguments; for example, repeated use of `zfdir /pub/gnu' will only require the directory to be retrieved on the first call. Alternatively, this cache can be re-viewed with the -r option. As relative directories will confuse zfdir, the -f option can be used to force the cache to be flushed before the directory is listed. The option -d will delete both caches without showing a directory listing; it will also delete the cache of file names in the current remote directory, if any.
Note that this requires a commonly implemented, but non-standard, version of the FTP protocol, so is not guaranteed to work on all servers.
In the first form, copy remote-file from the server to the local file local-file.
In the second form, copy all the remote files rfile1 ... into the local directory ldir retaining the same basenames. This assumes UNIX directory semantics.
With the option -r, if any of the files are directories they are sent recursively with all their subdirectories, including files beginning with `.'. This requires that the remote machine understand UNIX file semantics, since `/' is used as a directory separator.
With two arguments, copy local-file to the server as remote-file.
With more than two arguments, copy all the local files lfile1 ... into the existing remote directory rdir retaining the same basenames. This assumes UNIX directory semantics.
A problem arises if you attempt to use zfpcp lfile1 rdir, i.e. the second form of copying but with two arguments, as the command has no simple way of knowing if rdir corresponds to a directory or a filename. It attempts to resolve this in various ways. First, if the rdir argument is `.' or `..' or ends in a slash, it is assumed to be a directory. Secondly, if the operation of copying to a remote file in the first form failed, and the remote server sends back the expected failure code 553 and a reply including the string `Is a directory', then zfpcp will retry using the second form.
With no arguments, zfsession prints the name of the current session; with the option -l it lists all sessions which currently exist, and with the option -v it gives a verbose list showing the host and directory for each session, where the current session is marked with an asterisk. With -o, it will switch to the most recent previous session.
With -d, the given session (or else the current one) is removed; everything to do with it is completely forgotten. If it was the only session, a new session called `default' is created and made current. It is safest not to delete sessions while background commands using zftp are active.
The operation is performed using pipes, so it is required that the connections still be valid in a subshell, which is not the case under versions of some operating systems, presumably due to a system bug.
If not given an argument, list the existing bookmarks and the points to which they refer in the form user@host:directory; this is the format in which they are stored, and the file may be edited directly.
With the option -n, the bookmark is taken to be a nickname stored by the ncftp program in its bookmark file, which is assumed to be ~/.ncftp/bookmarks. The function works identically in other ways. Note that there is no mechanism for adding or modifying ncftp bookmarks from the zftp functions.
Currently this requires perl version 5 to perform the conversion from GMT to local time. This is unfortunately difficult to do using shell code alone.
chpwd() { if [[ -n $ZFTP_USER ]]; then zftp_chpwd else # usual chpwd e.g put host:directory in title bar fi }
fits in well.
Various styles are available using the standard shell style mechanism, described in zshmodules(1). Briefly, the command `zstyle ':zftp:*' style value ...'. defines the style to have value value; more than one value may be given, although that is not useful in the cases described here. These values will then be used throughout the zftp function system. For more precise control, the first argument, which gives a context in which the style applies, can be modified to include a particular function, as for example `:zftp:zfget': the style will then have the given value only in the zfget function. Values for the same style in different contexts may be set; the most specific function will be used, where strings are held to be more specific than patterns, and longer patterns and shorter patterns. Note that only the top level function name, as called by the user, is used; calling of lower level functions is transparent to the user. Hence modifications to the title bar in zftp_chpwd use the contexts :zftp:zfopen, :zftp:zfcd, etc., depending where it was called from. The following styles are understood:
When zfinit is run, if this style is not defined for the context :zftp:*, it will be set to `bar'.
As described for progress, zfinit will force this to default to 1.
As described for progress, zfinit will force this to default to 1.
When zfinit is run, it will determine whether chpwd exists and if so it will set the default value for the style to 1 if none exists already.
Note that there is also an associative array zfconfig which contains values used by the function system. This should not be modified or overwritten.
The commands for retrieving files usually perform filename generation (globbing) on their arguments; this can be turned off by passing the option -G to each of the commands. Normally this operates by retrieving a complete list of files for the directory in question, then matching these locally against the pattern supplied. This has the advantage that the full range of zsh patterns (respecting the setting of the option EXTENDED_GLOB) can be used. However, it means that the directory part of a filename will not be expanded and must be given exactly. If the remote server does not support the UNIX directory semantics, directory handling is problematic and it is recommended that globbing only be used within the current directory. The list of files in the current directory, if retrieved, will be cached, so that subsequent globs in the same directory without an intervening zfcd are much faster.
If the remote-glob style (see above) is set, globbing is instead performed on the remote host: the server is asked for a list of matching files. This is highly dependent on how the server is implemented, though typically UNIX servers will provide support for basic glob patterns. This may in some cases be faster, as it avoids retrieving the entire list of directory contents.
As described for the zfopen command, a subsequent zfopen with no parameters will reopen the connection to the last host (this includes connections made with the zfanon command). Opened in this fashion, the connection starts in the default remote directory and will remain open until explicitly closed.
Automatic re-opening is also available. If a connection is not currently open and a command requiring a connection is given, the last connection is implicitly reopened. In this case the directory which was current when the connection was closed again becomes the current directory (unless, of course, the command given changes it). Automatic reopening will also take place if the connection was close by the remote server for whatever reason (e.g. a timeout). It is not available if the -1 option to zfopen or zfanon was used.
Furthermore, if the command issued is a file transfer, the connection will be closed after the transfer is finished, hence providing a one-shot mode for transfers. This does not apply to directory changing or listing commands; for example a zfdir may reopen a connection but will leave it open. Also, automatic closure will only ever happen in the same command as automatic opening, i.e a zfdir directly followed by a zfget will never close the connection automatically.
Information about the previous connection is given by the zfstat function. So, for example, if that reports:
Session: default Not connected. Last session: ftp.bar.com:/pub/textfiles
then the command zfget file.txt will attempt to reopen a connection to ftp.bar.com, retrieve the file /pub/textfiles/file.txt, and immediately close the connection again. On the other hand, zfcd .. will open the connection in the directory /pub and leave it open.
Note that all the above is local to each session; if you return to a previous session, the connection for that session is the one which will be reopened.
Completion of local and remote files, directories, sessions and bookmarks is supported. The older, compctl-style completion is defined when zfinit is called; support for the new widget-based completion system is provided in the function Completion/Zsh/Command/_zftp, which should be installed with the other functions of the completion system and hence should automatically be available.
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