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1. Solaris
I have recently built a new server and patched Soalris 10 up tp latest bundle etc...
When I run a decompress using the format zcat fred.Z |tar -xvf - it runs at a very slow rate.
A similiar server which is less powerful runs over twice as quick.
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2. Shell Programming and Scripting
Hello,
When i lauches this command
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3. Shell Programming and Scripting
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Code
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1
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4. Shell Programming and Scripting
I created a backup script that emails all the admins when the backup is complete and attaches a log file of what what backed up. On occasion, something happens in which the backups stop working, I started "grep"ing around /var/log/syslog and I usually find the smoking gun. My goal is to zcat... (8 Replies)
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5. Shell Programming and Scripting
Hi,
Like
cat file1 file2 > file
Can I do
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6. UNIX for Advanced & Expert Users
I have a program............
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#include<unistd.h>
main()
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if(fork == 0)
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7. Programming
pls explain me how this works....
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8. Linux
Hi
I am trying to extract a <filename>.tar.Z on a SLES machine using zcat.
The command I am using is
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When I use the above I get the following message
tar: Read 7168 bytes from -
I think the message is benign because I see that my files where... (2 Replies)
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9. UNIX for Dummies Questions & Answers
ls displays files in tabbed output. Say a directory contains 3 files. ls will list all 3 in one line. So, I expect ls | wc -l to give 1, but it counts the nr of files and gives 3.
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10. UNIX for Dummies Questions & Answers
Hi all
I have more than 1000 files in a folder and when ever i use a "compress" or "zcat" command it give error
/bin/zcat: Arg list too long. .
any solution for this :o (3 Replies)
Discussion started by: muneebr
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compress(1) User Commands compress(1)
NAME
compress, uncompress, zcat - compress, uncompress files or display expanded files
SYNOPSIS
compress [-fv] [-b bits] [file...]
compress [-cfv] [-b bits] [file]
uncompress [-cfv] [file...]
zcat [file...]
DESCRIPTION
compress
The compress utility will attempt to reduce the size of the named files by using adaptive Lempel-Ziv coding. Except when the output is to
the standard output, each file will be replaced by one with the extension .Z, while keeping the same ownership modes, change times and mod-
ification times. If appending the .Z to the file pathname would make the pathname exceed 1023 bytes, the command will fail. If no files are
specified, the standard input will be compressed to the standard output.
The amount of compression obtained depends on the size of the input, the number of bits per code, and the distribution of common sub-
strings. Typically, text such as source code or English is reduced by 50-60%. Compression is generally much better than that achieved by
Huffman coding (as used in pack(1)) and it takes less time to compute. The bits parameter specified during compression is encoded within
the compressed file, along with a magic number to ensure that neither decompression of random data nor recompression of compressed data is
subsequently allowed.
uncompress
The uncompress utility will restore files to their original state after they have been compressed using the compress utility. If no files
are specified, the standard input will be uncompressed to the standard output.
This utility supports the uncompressing of any files produced by compress. For files produced by compress on other systems, uncompress sup-
ports 9- to 16-bit compression (see -b).
zcat
The zcat utility will write to standard output the uncompressed form of files that have been compressed using compress. It is the equiva-
lent of uncompress -c. Input files are not affected.
OPTIONS
The following options are supported:
-c Writes to the standard output; no files are changed and no .Z files are created. The behavior of zcat is identical to that of
`uncompress -c'.
-f When compressing, forces compression of file, even if it does not actually reduce the size of the file, or if the corresponding
file.Z file already exists. If the -f option is not given, and the process is not running in the background, prompts to verify
whether an existing file.Z file should be overwritten. When uncompressing, does not prompt for overwriting files. If the -f
option is not given, and the process is not running in the background, prompts to verify whether an existing file should be over-
written. If the standard input is not a terminal and -f is not given, writes a diagnostic message to standard error and exits with
a status greater than 0.
-v Verbose. Writes to standard error messages concerning the percentage reduction or expansion of each file.
-b bits Sets the upper limit (in bits) for common substring codes. bits must be between 9 and 16 (16 is the default). Lowering the number
of bits will result in larger, less compressed files.
OPERANDS
The following operand is supported:
file A path name of a file to be compressed by compress, uncompressed by uncompress, or whose uncompressed form is written to standard
out by zcat. If file is -, or if no file is specified, the standard input will be used.
USAGE
See largefile(5) for the description of the behavior of compress, uncompress, and zcat when encountering files greater than or equal to 2
Gbyte ( 2**31 bytes).
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment variables that affect the execution of compress, uncompress, and zcat: LANG,
LC_ALL, LC_CTYPE, LC_MESSAGES, and NLSPATH.
EXIT STATUS
The following error values are returned:
0 Successful completion.
1 An error occurred.
2 One or more files were not compressed because they would have increased in size (and the -f option was not specified).
>2 An error occurred.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWesu |
+-----------------------------+-----------------------------+
|CSI |Enabled |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
SEE ALSO
ln(1), pack(1), attributes(5), environ(5), largefile(5), standards(5)
DIAGNOSTICS
Usage: compress [-fvc] [-b maxbits] [file... ]
Invalid options were specified on the command line.
Missing maxbits
Maxbits must follow -b, or invalid maxbits, not a numeric value.
file: not in compressed format
The file specified to uncompress has not been compressed.
file: compressed with xxbits, can only handle yybits
file was compressed by a program that could deal with more bits than the compress code on this machine. Recompress the file with
smaller bits.
file: already has .Z suffix -- no change
The file is assumed to be already compressed. Rename the file and try again.
file: already exists; do you wish to overwrite (y or n)?
Respond y if you want the output file to be replaced; n if not.
uncompress: corrupt input
A SIGSEGV violation was detected, which usually means that the input file is corrupted.
Compression: xx.xx%
Percentage of the input saved by compression. (Relevant only for -v.)
- - not a regular file: unchanged
When the input file is not a regular file, (such as a directory), it is left unaltered.
- - has xx other links: unchanged
The input file has links; it is left unchanged. See ln(1) for more information.
- - file unchanged
No savings are achieved by compression. The input remains uncompressed.
filename too long to tack on .Z
The path name is too long to append the .Z suffix.
NOTES
Although compressed files are compatible between machines with large memory, -b 12 should be used for file transfer to architectures with a
small process data space (64KB or less).
compress should be more flexible about the existence of the .Z suffix.
SunOS 5.10 9 Sep 1999 compress(1)