Unix and Linux Tips

Jumat, 14 Oktober 2011

Unix Tip: REWIND A TAPE FAST

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3535 - October 14, 2011

http://www.ugu.com/sui/ugu/show?tip.today

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REWIND A TAPE FAST

What's the fastest way to rewind a tape without
using "mt" or other tape software?

From a bourne or korn shell, Just type:

$ < /dev/[tapedevice]
$ < /dev/rst8

and watch it rewind...

This tip generously supported by: ulli@ucrc.org

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Kamis, 13 Oktober 2011

Unix Tip: CRYPT AN ASCII FILE

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UNIX HOT TIP

Unix Tip 3534 - October 13, 2011

http://www.ugu.com/sui/ugu/show?tip.today

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CRYPT AN ASCII FILE

An ascii file can be easily encrypted and
decrypted.

To encrypt simply pipe the STDOUT of
the file to "crypt" and redirect it to
a new file name. Enter a passowrd when
prompted with "Enter key".

$ cat foo | crypt > foo.e
Enter key:

To unencrypt simply pipe the STDOUT of
the encrypted file to "crpyt" and
redirect it to a new file name. Enter
a passowrd when prompted with
"Enter key".

$ cat foo.e | crypt > foo.new
Enter key:

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Rabu, 12 Oktober 2011

Unix Tip: MORE AND VI OR MORE VI

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3533 - October 12, 2011

http://www.ugu.com/sui/ugu/show?tip.today

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MORE AND VI OR MORE VI

To edit a file after looking at it with "more"
Press the letter "v" key and you will be placed
in a vi session.

Quitting the vi session will bring you back
to viewing the file with the "more" command

This will not work with piping a file to "more".

This works:

$ more /etc/hosts

This does not:

$ cat /etc/hosts | more

Unix Guru Universe - www.ugu.com - tips@ugu.com - Copyright 1994-2001
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Selasa, 11 Oktober 2011

Unix Tip: EXTRACT CORRUPTED TAR FILE

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3532 - October 11, 2011

http://www.ugu.com/sui/ugu/show?tip.today

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EXTRACT CORRUPTED TAR FILE

In many case if there is a corrupted tar file,
the following command can be used in an attempt
to extract the file:

% cat [tar-filename] | tar -xvf -

NOTE: Where "-" is the STDOUT

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Senin, 10 Oktober 2011

Unix Tip: EDIT A LOST FILE

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3531 - October 10, 2011

http://www.ugu.com/sui/ugu/show?tip.today

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EDIT A LOST FILE

Forget where you put your files?

Rather than specifying an absolute pathname,
use command substitution instead.

Instead of:

% vi /usr/local/bin/foo

Try:

% vi `which foo`

NOTE: files must be in your path for "which" to find them.

This tip generously supported by: thockin@ais.net

Unix Guru Universe - www.ugu.com - tips@ugu.com - Copyright 1994-2001
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Minggu, 09 Oktober 2011

Unix Tip: COLLECTING FILES

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3530 - October 9, 2011

http://www.ugu.com/sui/ugu/show?tip.today

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COLLECTING FILES

NOTE: Depending on how the command is used, an
admin with root can abuse their privileges.

If there are similar files on a system and you wish
to collect the contents of those files (possibly
for security reasons) the following command
will search a system for a filename and output
the contents into a file to be viewed.

# find / -name .rhosts -perm -004 -print > rhosts 2>e &

Another use was brought up that one could
learn what other commands users use. They
may have thought of some tricks you may not have:

# find / -name .bash_history -perm -004 -print >o 2>e &

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Sabtu, 08 Oktober 2011

Unix Tip: FIND THE HOG

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3529 - October 8, 2011

http://www.ugu.com/sui/ugu/show?tip.today

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FIND THE HOG

Hot Tip for Space Cops: (aren't we all?)

If your users keep using up all the space in your home directory,
here is a way to apprehend the top offenders.

cd /home
du -ks *|sort -nr|pg

(Note: The "k" option may not be necessary in non-posix systems.)
This string will show you all the directory sizes in order,
largest first. Now if you are going to do a little cleanup yourself,
in one of those directories run:

ls -ls|sort -nr|pg

This will list files by size largest first. That way when you do your compress,
move, or remove, you may actually reclaim a significant amount of space.

This tip generously supported by: uspncjpf@ibmmail.com

Unix Guru Universe - www.ugu.com - tips@ugu.com - Copyright 1994-2001
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