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git-svn-id: svn+ssh://atelier.inf.usi.ch/home/bevilj/group-1@269 a672b425-5310-4d7a-af5c-997e18724b81
112 lines
5.5 KiB
HTML
112 lines
5.5 KiB
HTML
---
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layout: page
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category-page: fs
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category-title: FileSystem
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tags: directory list copy cp
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author: Mattia Hijman
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title: touch
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previous-page: pages/fs/rm.html
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---
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In the first synopsis form, the cp utility copies the contents of the source_file to the target_file. <br>
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In the second synopsis form, the contents of each named source_file is copied to the destination
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target_directory. <br>
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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>
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The following options are available:<br>
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<ul>
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<li> <b>-a</b>
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Same as -pPR options. Preserves structure and attributes of files
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but not directory structure.</li>
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<li> <b>-f</b>
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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.)
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The target file is not unlinked before the copy. Thus, any existing access rights will be retained.</li>
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<li> <b>-H</b>
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If the -R option is specified, symbolic links on the command line are followed. </li>
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<li> <b>-i</b> Cause cp to write a prompt to the standard error output before
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copying a file that would overwrite an existing file. If the
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response from the standard input begins with the character `y' or
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`Y', the file copy is attempted.</li>
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<li> <b>-L</b> If the -R option is specified, all symbolic links are followed.</li>
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<li> <b>-n</b> Do not overwrite an existing file. </li>
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<li> <b>-P </b> If the -R option is specified, no symbolic links are followed.
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This is the default.</li>
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<li> <b>-p</b> Cause cp to preserve the following attributes of each source file
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in the copy: modification time, access time, file flags, file mode,
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user ID, and group ID, as allowed by permissions. Access Control
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Lists (ACLs) and Extended Attributes (EAs), including resource
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forks, will also be preserved.
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If the user ID and group ID cannot be preserved, no error message
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is displayed and the exit value is not altered.
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If the source file has its set-user-ID bit on and the user ID can-
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not be preserved, the set-user-ID bit is not preserved in the
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copy's permissions. If the source file has its set-group-ID bit on
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and the group ID cannot be preserved, the set-group-ID bit is not
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preserved in the copy's permissions. If the source file has both
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its set-user-ID and set-group-ID bits on, and either the user ID or
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group ID cannot be preserved, neither the set-user-ID nor set group-ID bits are preserved in the copy's permissions.</li>
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<li> <b>-R</b> If source_file designates a directory, cp copies the directory and
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the entire subtree connected at that point. If the source_file
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ends in a /, the contents of the directory are copied rather than
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the directory itself. This option also causes symbolic links to be
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copied, rather than indirected through, and for cp to create spe-
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cial files rather than copying them as normal files. Created
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directories have the same mode as the corresponding source direc-
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tory, unmodified by the process' umask.
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In -R mode, cp will continue copying even if errors are detected.
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Note that cp copies hard-linked files as separate files. If you
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need to preserve hard links, consider using tar(1), cpio(1), or
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pax(1) instead.</li>
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<li> <b>-v</b> Cause cp to be verbose, showing files as they are copied.</li>
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<li> <b>-X</b> Do not copy Extended Attributes (EAs) or resource forks.</li>
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<li> <b>-c</b> copy files using clonefile(2)</li>
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</ul>
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For each destination file that already exists, its contents are overwrit-
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ten if permissions allow. Its mode, user ID, and group ID are unchanged
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unless the -p option was specified.
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In the second synopsis form, target_directory must exist unless there is
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only one named source_file which is a directory and the -R flag is speci-
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fied.
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If the destination file does not exist, the mode of the source file is
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used as modified by the file mode creation mask (umask, see csh(1)). If
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the source file has its set-user-ID bit on, that bit is removed unless
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both the source file and the destination file are owned by the same user.
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If the source file has its set-group-ID bit on, that bit is removed
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unless both the source file and the destination file are in the same
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group and the user is a member of that group. If both the set-user-ID
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and set-group-ID bits are set, all of the above conditions must be ful-
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filled or both bits are removed.
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Appropriate permissions are required for file creation or overwriting.
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Symbolic links are always followed unless the -R flag is set, in which
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case symbolic links are not followed, by default. The -H or -L flags (in
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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
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option is specified. In addition, these options override each other and
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the command's actions are determined by the last one specified.
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If cp receives a SIGINFO (see the status argument for stty(1)) signal,
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the current input and output file and the percentage complete will be
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written to the standard output.
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