utils.sgml

cygwin, 著名的在win32下模拟unix操作系统的东东

SIGALRM     14    alarm clock
SIGTERM     15    software termination signal from kill
SIGURG      16    urgent condition on IO channel
SIGSTOP     17    sendable stop signal not from tty
SIGTSTP     18    stop signal from tty
SIGCONT     19    continue a stopped process
SIGCHLD     20    to parent on child stop or exit
SIGTTIN     21    to readers pgrp upon background tty read
SIGTTOU     22    like TTIN for output if (tp->t_local&LTOSTOP)
SIGPOLL     23    System V name for SIGIO
SIGXCPU     24    exceeded CPU time limit
SIGXFSZ     25    exceeded file size limit
SIGVTALRM   26    virtual time alarm
SIGPROF     27    profiling time alarm
SIGWINCH    28    window changed
SIGLOST     29    resource lost (eg, record-lock lost)
SIGUSR1     30    user defined signal 1
SIGUSR2     31    user defined signal 2
</screen>

</sect2>

<sect2 id="mkgroup"><title>mkgroup</title>

<screen>
Usage: mkgroup [OPTION]... [domain]

This program prints a /etc/group file to stdout

Options:
   -l,--local             print local group information
   -d,--domain            print global group information from the domain
                          specified (or from the current domain if there is
                          no domain specified)
   -o,--id-offset offset  change the default offset (10000) added to uids
                          in domain accounts.
   -s,--no-sids           don't print SIDs in pwd field
                          (this affects ntsec)
   -u,--users             print user list in gr_mem field
   -h,--help              print this message

   -v,--version           print version information and exit

One of `-l' or `-d' must be given on NT/W2K.
</screen>

<para>The <command>mkgroup</command> program can be used to help
configure your Windows system to be more UNIX-like by creating an
initial <filename>/etc/group</filename> substitute (some commands need this
file) from your system information. It only works on the NT series
(Windows NT, 2000, and XP). <command>mkgroup</command> does not work on 
the Win9x series (Windows 95, 98, and Me) because they lack the security model 
to support it. To initially set up your machine, you'd do something like 
this:</para>

<example><title>Setting up the groups file</title>
<screen>
<prompt>$</prompt> <userinput>mkdir /etc</userinput>
<prompt>$</prompt> <userinput>mkgroup -l &gt; /etc/group</userinput>
</screen>
</example>

<para>Note that this information is static.  If you change the group
information in your system, you'll need to regenerate the group file
for it to have the new information.</para>

<para>The <literal>-d</literal> and <literal>-l</literal> options
allow you to specify where the information comes from, either the
local machine or the default (or given) domain.  The <literal>-o</literal>
option allows for special cases (such as multiple domains) where the GIDs 
might match otherwise. The <literal>-s</literal>
option omits the NT Security Identifier (SID).  For more information on 
SIDs, see <Xref Linkend="ntsec"> in the Cygwin User's Guide.  The
<literal>-u</literal> option causes <command>mkgroup</command> to 
enumerate the users for each group, placing the group members in the 
gr_mem (last) field.  Note that this can greatly increase
the time for <command>mkgroup</command> to run in a large domain.
</para>

</sect2>

<sect2 id="mkpasswd"><title>mkpasswd</title>

<screen>
Usage: mkpasswd [OPTION]... [domain]

This program prints a /etc/passwd file to stdout

Options:
   -l,--local              print local user accounts
   -d,--domain             print domain accounts (from current domain
                           if no domain specified)
   -o,--id-offset offset   change the default offset (10000) added to uids
                           in domain accounts.
   -g,--local-groups       print local group information too
                           if no domain specified
   -m,--no-mount           don't use mount points for home dir
   -s,--no-sids            don't print SIDs in GCOS field
                           (this affects ntsec)
   -p,--path-to-home path  use specified path instead of user account home dir
   -u,--username username  only return information for the specified user
   -h,--help               displays this message
   -v,--version            version information and exit

One of `-l', `-d' or `-g' must be given on NT/W2K.
</screen>

<para>The <command>mkpasswd</command> program can be used to help
configure your Windows system to be more UNIX-like by creating an
initial <filename>/etc/passwd</filename> substitute (some commands
need this file) from your system information. It only works on the NT series
(Windows NT, 2000, and XP). <command>mkpasswd</command> does not work on 
the Win9x series (Windows 95, 98, and Me) because they lack the security model 
to support it. To initially set up your machine, you'd do something like 
this:</para>

<example><title>Setting up the passwd file</title>
<screen>
<prompt>$</prompt> <userinput>mkdir /etc</userinput>
<prompt>$</prompt> <userinput>mkpasswd -l &gt; /etc/passwd</userinput>
</screen>
</example>

<para>Note that this information is static.  If you change the user
information in your system, you'll need to regenerate the passwd file
for it to have the new information.</para>

<para>The <literal>-d</literal> and <literal>-l</literal> options
allow you to specify where the information comes from, either the
local machine or the default (or given) domain.  The <literal>-o</literal>
option allows for special cases (such as multiple domains) where the UIDs
might match otherwise.  The <literal>-g</literal> option creates a local
user that corresponds to each local group. This is because NT assigns groups
file ownership.  The <literal>-m</literal> option bypasses the current
mount table so that, for example, two users who have a Windows home 
directory of H: could mount them differently.  The <literal>-s</literal>
option omits the NT Security Identifier (SID).  For more information on
SIDs, see <Xref Linkend="ntsec"> in the Cygwin User's Guide.  The
<literal>-p</literal> option causes <command>mkpasswd</command> to
use a prefix other than <literal>/home/</literal>. For example, this command:

<example><title>Using an alternate home root</title>
<screen>
<prompt>$</prompt> <userinput>mkpasswd -l -p "$(cygpath -H)" &gt; /etc/passwd</userinput>
</screen>
</example>

would put local users' home directories in the Windows 'Profiles' directory. 
The <literal>-u</literal> option allows <command>mkpasswd</command> to 
search for a specific username, greatly reducing the amount of time it 
takes in a large domain.</para>

</sect2>

<sect2 id="mount"><title>mount</title>

<screen>
Usage: mount [OPTION] [&lt;win32path&gt; &lt;posixpath&gt;]
  -b, --binary                  text files are equivalent to binary files
                                (newline = \n)
  -c, --change-cygdrive-prefix  change the cygdrive path prefix to &lt;posixpath&gt;
  -f, --force                   force mount, don't warn about missing mount
                                point directories
  -h, --help                    output usage information and exit
  -m, --mount-commands          write mount commands to replace user and
                                system mount points and cygdrive prefixes
  -p, --show-cygdrive-prefix    show user and/or system cygdrive path prefix
  -s, --system     (default)    add system-wide mount point
  -t, --text       (default)    text files get \r\n line endings
  -u, --user                    add user-only mount point
  -v, --version                 output version information and exit
  -x, --executable              treat all files under mount point as executables
  -E, --no-executable           treat all files under mount point as 
                                non-executables
  -X, --cygwin-executable       treat all files under mount point as cygwin
                                executables
</screen>

<para>The <command>mount</command> program is used to map your drives
and shares onto Cygwin's simulated POSIX directory tree, much like as is
done by mount commands on typical UNIX systems.  Please see
<Xref Linkend="mount-table"> for more information on the concepts
behind the Cygwin POSIX file system and strategies for using
mounts. To remove mounts, use <command>umount</command></para>

<sect3><title>Using mount</title>

<para>If you just type <command>mount</command> with no parameters, it
will display the current mount table for you.</para>

<example>
<title>Displaying the current set of mount points</title>
<screen>
<prompt>c:\cygwin\&gt;</prompt> <userinput>mount</userinput>
c:\cygwin\bin on /usr/bin type system (binmode)
c:\cygwin\lib on /usr/lib type system (binmode)
c:\cygwin on / type system (binmode)
c: on /c type user (binmode,noumount)
d: on /d type user (binmode,noumount)
</screen>
</example>

<para>In this example, c:\cygwin is the POSIX root and D drive is mapped to
<filename>/d</filename>.  Note that in this case, the root mount is a
system-wide mount point that is visible to all users running Cygwin
programs, whereas the <filename>/d</filename> mount is only visible
to the current user.</para>

<para>The <command>mount</command> utility is also the mechanism for
adding new mounts to the mount table.  The following example
demonstrates how to mount the directory
<filename>\\pollux\home\joe\data</filename> to <filename>/data</filename>.
</para>

<example>
<title>Adding mount points</title>
<screen>
<prompt>c:\cygwin\&gt;</prompt> <userinput>ls /data</userinput>
ls: /data: No such file or directory
<prompt>c:\cygwin\&gt;</prompt> <userinput>mount \\pollux\home\joe\data /data</userinput>
mount: warning - /data does not exist!
<prompt>c:\cygwin\&gt;</prompt> <userinput>mount</userinput>
\\pollux\home\joe\data on /data type sytem (binmode)
c:\cygwin\bin on /usr/bin type system (binmode)
c:\cygwin\lib on /usr/lib type system (binmode)
c:\cygwin on / type system (binmode)
c: on /c type user (binmode,noumount)
d: on /d type user (binmode,noumount)
</screen>
</example>

<para>Note that <command>mount</command> was invoked from the Windows
command shell in the previous example.  In many Unix shells, including
bash, it is legal and convenient to use the forward "/" in Win32
pathnames since the "\" is the shell's escape character. </para>

<para>The <literal>-s</literal> flag to <command>mount</command> is used to add a mount
in the system-wide mount table used by all Cygwin users on the system,
instead of the user-specific one.  System-wide mounts are displayed
by <command>mount</command> as being of the "system" type, as is the
case for the <filename>/</filename> partition in the last example.
Under Windows NT, only those users with Administrator priviledges are
permitted to modify the system-wide mount table.</para>

<para>Note that a given POSIX path may only exist once in the user
table and once in the global, system-wide table.  Attempts to replace
the mount will fail with a busy error.  The <literal>-f</literal> (force) flag causes
the old mount to be silently replaced with the new one.  It will also
silence warnings about the non-existence of directories at the Win32
path location.</para>

<para>The <literal>-b</literal> flag is used to instruct Cygwin to treat binary and
text files in the same manner by default.  Binary mode mounts are
marked as "binmode" in the Flags column of <command>mount</command>
output.  By default, mounts are in text mode ("textmode" in the Flags
column).</para>

<para>Normally, files ending in certain extensions (.exe, .com, .bat, .cmd) 
are assumed to be executable.  Files whose first two characters begin with 
'#!' are also considered to be executable.  
The <literal>-x</literal> flag is used to instruct Cygwin that the 
mounted file is "executable".  If the <literal>-x</literal> flag is used 
with a directory then all files in the directory are executable.  
This option allows other files to be marked as executable and avoids the 
overhead of opening each file to check for a '#!'.  The <literal>-X</literal>
option is very similar to <literal>-x</literal>, but also prevents Cygwin
from setting up commands and environment variables for a normal Windows 
program, adding another small performance gain.  The opposite of these 
flags is the <literal>-E</literal> flag, which means that no files should be 
marked as executable.  </para>

<para>
The <literal>-m</literal> option causes the <command>mount</command> utility
to output a series of commands that could recreate both user and system mount 
points. You can save this output as a backup when experimenting with the
mount table. It also makes moving your settings to a different machine
much easier.
</para>

</sect3>

<sect3><title>Cygdrive mount points</title>

<para>Whenever Cygwin cannot use any of the existing mounts to convert
from a particular Win32 path to a POSIX one, Cygwin will, instead,
convert to a POSIX path using a default mount point:
<filename>/cygdrive</filename>.  For example, if Cygwin accesses
<filename>z:\foo</filename> and the z drive is not currently in the
mount table, then <filename>z:\</filename> will be accessible as
<filename>/cygdrive/z</filename>.  The <command>mount</command> utility 
can be used to change this default automount prefix through the use of the
"--change-cygdrive-prefix" option.  In the following example, we will
set the automount prefix to <filename>/</filename>:</para>

<example>
<title>Changing the default prefix</title>
<screen>
<prompt>c:\cygwin\&gt;</prompt> <userinput>mount --change-cygdrive-prefix /</userinput>
</screen>
</example>

<para>Note that you if you set a new prefix in this manner, you can
specify the <literal>-s</literal> flag to make this the system-wide default 
prefix.  By default, the cygdrive-prefix applies only to the current user.  
You can always see the user and system cygdrive prefixes with the 
<literal>-p</literal> option.  Using the <literal>-b</literal>
flag with <literal>--change-cygdrive-prefix</literal> makes all new 
automounted filesystems default to binary mode file accesses.</para>

</sect3>

<sect3><title>Limitations</title>

<para>Limitations: there is a hard-coded limit of 30 mount
points.  Also, although you can mount to pathnames that do not start
with "/", there is no way to make use of such mount points.</para>

<para>Normally the POSIX mount point in Cygwin is an existing empty
directory, as in standard UNIX. If this is the case, or if there is a
place-holder for the mount point (such as a file, a symbolic link
pointing anywhere, or a non-empty directory), you will get the expected
behavior. Files present in a mount point directory before the mount
become invisible to Cygwin programs.
</para>

<para>It is sometimes desirable to mount to a non-existent directory,
for example to avoid cluttering the root directory with names
such as
<filename>a</filename>, <filename>b</filename>, <filename>c</filename>
pointing to disks.
Although <command>mount</command> will give you a warning, most
everything will work properly when you refer to the mount point
explicitly.  Some strange effects can occur however.
For example if your current working directory is
<filename>/dir</filename>,
say, and <filename>/dir/mtpt</filename> is a mount point, then
<filename>mtpt</filename> will not show up in an <command>ls</command>
or
<command>echo *</command> command and <command>find .</command> will
not
find <filename>mtpt</filename>.
</para>