| .\" -*- nroff -*- |
| .TH CHATTR 1 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@" |
| .SH NAME |
| chattr \- change file attributes on a Linux second extended file system |
| .SH SYNOPSIS |
| .B chattr |
| [ |
| .B \-RV |
| ] |
| [ |
| .B \-v |
| .I version |
| ] |
| [ |
| .I mode |
| ] |
| .I files... |
| .SH DESCRIPTION |
| .B chattr |
| changes the file attributes on a Linux second extended file system. |
| .PP |
| The format of a symbolic mode is +-=[ASacdisu]. |
| .PP |
| The operator `+' causes the selected attributes to be added to the |
| existing attributes of the files; `-' causes them to be removed; and |
| `=' causes them to be the only attributes that the files have. |
| .PP |
| The letters `ASacdisu' select the new attributes for the files: |
| don't update atime (A), synchronous updates (S), append only (a), |
| compressed (c), immutable (i), no dump (d), |
| secure deletion (s), and undeletable (u). |
| .SH OPTIONS |
| .TP |
| .B \-R |
| Recursively change attributes of directories and their contents. |
| Symbolic links encountered during recursive directory traversals are |
| ignored. |
| .TP |
| .B \-V |
| Be verbose with chattr's output and print the program version. |
| .TP |
| .BI \-v " version" |
| Set the file's version/generation number. |
| .SH ATTRIBUTES |
| When a file with the 'A' attribute set is modified, its atime record is |
| not modified. This avoids a certain amount of disk I/O for laptop |
| systems. |
| .PP |
| A file with the `a' attribute set can only be open in append mode for writing. |
| Only the superuser can set or clear this attribute. |
| .PP |
| A file with the `c' attribute set is automatically compressed on the disk |
| by the kernel. A read from this file returns uncompressed data. A write to |
| this file compresses data before storing them on the disk. |
| .PP |
| A file with the `d' attribute set is not candidate for backup when the |
| .BR dump (8) |
| program is run. |
| .PP |
| A file with the `i' attribute cannot be modified: it cannot be deleted or |
| renamed, no link can be created to this file and no data can be written |
| to the file. Only the superuser can set or clear this attribute. |
| .PP |
| When a file with the `s' attribute set is deleted, its blocks are zeroed and |
| written back to the disk. |
| .PP |
| When a file with the `S' attribute set is modified, |
| the changes are written synchronously on the disk; this is equivalent to |
| the `sync' mount option applied to a subset of the files. |
| .PP |
| When a file with the `u' attribute set is deleted, its contents are saved. |
| This allows the user to ask for its undeletion. |
| .PP |
| .SH AUTHOR |
| .B chattr |
| was written by Remy Card <card@masi.ibp.fr>, the developer and maintainer |
| of the ext2 fs. |
| .SH BUGS AND LIMITATIONS |
| As of ext2 fs 0.5a, the `c' and `u' attribute are not honoured by the kernel |
| code. As of the Linux 2.0 kernel, the 'A' attribute is not yet supported by |
| the kernel code. (The noatime code is still in testing.) |
| .PP |
| These attributes will be implemented in a future ext2 fs version. |
| .SH AVAILABILITY |
| .B chattr |
| is part of the e2fsprogs package and is available for anonymous |
| ftp from tsx-11.mit.edu in /pub/linux/packages/ext2fs. |
| .SH SEE ALSO |
| .BR lsattr (1) |