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new page about the copy command in the filesystem folder

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git-svn-id: svn+ssh://atelier.inf.usi.ch/home/bevilj/group-1@269 a672b425-5310-4d7a-af5c-997e18724b81
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site/pages/fs
cp.htmltouch.html

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---
layout: page
category-page: fs
category-title: FileSystem
tags: directory list copy cp
author: Mattia Hijman
title: touch
previous-page: pages/fs/rm.html
---
In the first synopsis form, the cp utility copies the contents of the source_file to the target_file. <br>
In the second synopsis form, the contents of each named source_file is copied to the destination
target_directory. <br>
The names of the files themselves are not changed. If cp detects an attempt to copy a file to itself, the copy will fail. <br>
The following options are available:<br>
<ul>
<li> <b>-a</b>
Same as -pPR options. Preserves structure and attributes of files
but not directory structure.</li>
<li> <b>-f</b>
If the destination file cannot be opened, remove it and create a new file, without prompting for confirmation regardless of its permissions. (The -f option overrides any previous -n option.)
The target file is not unlinked before the copy. Thus, any existing access rights will be retained.</li>
<li> <b>-H</b>
If the -R option is specified, symbolic links on the command line are followed. </li>
<li> <b>-i</b> Cause cp to write a prompt to the standard error output before
copying a file that would overwrite an existing file. If the
response from the standard input begins with the character `y' or
`Y', the file copy is attempted.</li>
<li> <b>-L</b> If the -R option is specified, all symbolic links are followed.</li>
<li> <b>-n</b> Do not overwrite an existing file. </li>
<li> <b>-P </b> If the -R option is specified, no symbolic links are followed.
This is the default.</li>
<li> <b>-p</b> Cause cp to preserve the following attributes of each source file
in the copy: modification time, access time, file flags, file mode,
user ID, and group ID, as allowed by permissions. Access Control
Lists (ACLs) and Extended Attributes (EAs), including resource
forks, will also be preserved.
If the user ID and group ID cannot be preserved, no error message
is displayed and the exit value is not altered.
If the source file has its set-user-ID bit on and the user ID can-
not be preserved, the set-user-ID bit is not preserved in the
copy's permissions. If the source file has its set-group-ID bit on
and the group ID cannot be preserved, the set-group-ID bit is not
preserved in the copy's permissions. If the source file has both
its set-user-ID and set-group-ID bits on, and either the user ID or
group ID cannot be preserved, neither the set-user-ID nor set group-ID bits are preserved in the copy's permissions.</li>
<li> <b>-R</b> If source_file designates a directory, cp copies the directory and
the entire subtree connected at that point. If the source_file
ends in a /, the contents of the directory are copied rather than
the directory itself. This option also causes symbolic links to be
copied, rather than indirected through, and for cp to create spe-
cial files rather than copying them as normal files. Created
directories have the same mode as the corresponding source direc-
tory, unmodified by the process' umask.
In -R mode, cp will continue copying even if errors are detected.
Note that cp copies hard-linked files as separate files. If you
need to preserve hard links, consider using tar(1), cpio(1), or
pax(1) instead.</li>
<li> <b>-v</b> Cause cp to be verbose, showing files as they are copied.</li>
<li> <b>-X</b> Do not copy Extended Attributes (EAs) or resource forks.</li>
<li> <b>-c</b> copy files using clonefile(2)</li>
</ul>
For each destination file that already exists, its contents are overwrit-
ten if permissions allow. Its mode, user ID, and group ID are unchanged
unless the -p option was specified.
In the second synopsis form, target_directory must exist unless there is
only one named source_file which is a directory and the -R flag is speci-
fied.
If the destination file does not exist, the mode of the source file is
used as modified by the file mode creation mask (umask, see csh(1)). If
the source file has its set-user-ID bit on, that bit is removed unless
both the source file and the destination file are owned by the same user.
If the source file has its set-group-ID bit on, that bit is removed
unless both the source file and the destination file are in the same
group and the user is a member of that group. If both the set-user-ID
and set-group-ID bits are set, all of the above conditions must be ful-
filled or both bits are removed.
Appropriate permissions are required for file creation or overwriting.
Symbolic links are always followed unless the -R flag is set, in which
case symbolic links are not followed, by default. The -H or -L flags (in
conjunction with the -R flag) cause symbolic links to be followed as described above. The -H, -L and -P options are ignored unless the -R
option is specified. In addition, these options override each other and
the command's actions are determined by the last one specified.
If cp receives a SIGINFO (see the status argument for stty(1)) signal,
the current input and output file and the percentage complete will be
written to the standard output.

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layout: page
category-page: fs
category-title: FileSystem
tags: directory list remove delete erase
tags: directory list create new file
author: Mattia Hijman
title: touch
previous-page: pages/fs/rm.html