Unix and Linux Tips

Senin, 28 Februari 2011

Unix Tip: I SED BLANK

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3307 - February 28, 2011

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

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I SED BLANK

Using sed, you can remove blank lines, and
lines that contain only whitespace, from a
file using the following:

sed -e '/^[ ]*$/d' InputFile >OutputFile

Within the single quotes ('), the forward
slashes (/) delimit the regular expression
that will be interpreted by sed. The "d"
before the closing single quote, tells sed
to delete any lines that match the regular
expression.

Within the regular expression, the caret
(^) matches the beginning of a line.
The []* matches zero to many occurrences of
the character list between the open bracket
([) and the close bracket (]) (in the above
regular expression, you must insert a space
and a tab between the brackets). The dollar
sign ($) matches the end of a line.

These three constructs together match any
blank line or any line that contains only
spaces and tabs (in any combination).

Since the standard operation of sed is to
echo lines to stdout, all lines except blank
lines (or lines that only contain whitespace)
will be sent to OutputFile.

This tip generously supported by: tim.couger@wcom.com

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Minggu, 27 Februari 2011

Unix Tip: FILES OPENED BY A PROCESS

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3306 - February 27, 2011

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

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FILES OPENED BY A PROCESS

This is supported on Sun Solaris, not too sure about
other Unix flavours.

I badly wanted to find out all the files opened by
a process, and that is when I found pfiles.

Usage :
/usr/proc/bin/pfiles <pid>

Where pid is the process-id of the process.

It lists the inode numbers of all the files, opened
by that process.

This tip generously supported by: mdhar@miel.mot.com

Unix Guru Universe - www.ugu.com - tips@ugu.com - Copyright 1994-2001
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Sabtu, 26 Februari 2011

Unix Tip: BACKUP THE REMOTE ESSENTIALS

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3305 - February 26, 2011

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

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BACKUP THE REMOTE ESSENTIALS

There are many programs, data files, and especially
license files that sit out on remote workstations
and servers that you may should be backing up
remotely.

If backing up the entire system puts a strain
on your network, make sure that all the essential
files at least get backed up.

Some files may be
/var/flexlm
/usr/local/flexlm
/var/netls
/var/license
/etc/passwd
/etc/hosts
/etc/groups
/etc/netgroups
/etc/shadow
/vmunix
/kernel
etc....

Unix Guru Universe - www.ugu.com - tips@ugu.com - Copyright 1994-2001
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Jumat, 25 Februari 2011

Unix Tip: STRING REMOVAL

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3304 - February 25, 2011

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

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STRING REMOVAL

What the following does:

rm `ls -al | grep str | awk '{if ($9 !~ /^str/) {print $9}'`

Removes all files that contains the string "str" excepts
those that begin with it. Changing the !~ to =~ does the
opposite.

Unix Guru Universe - www.ugu.com - tips@ugu.com - Copyright 1994-2001
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Kamis, 24 Februari 2011

Unix Tip: KILLING MORE USERS

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3303 - February 24, 2011

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

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KILLING MORE USERS

*** SORRY ABOUT THE PEVIOUS NULL TIP IF YOU RECEIVED IT****

To kill all processes of a particular user from root
at unix prompt type:

# kill -9 `ps -fu username |awk '{ print $2 }'|grep -v PID`

We can also use the username as an argument and pass it from
command line, if this command is put as a script.

This tip generously supported by: merveille@lucent.com

Unix Guru Universe - www.ugu.com - tips@ugu.com - Copyright 1994-2001
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Rabu, 23 Februari 2011

Unix Tip: BASH HOTKEYS

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3302 - February 23, 2011

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

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BASH HOTKEYS

Bash provides many hot keys to ease use. Like
ctrl-l -- clear screen
ctrl-r -- does a search in the previously given commands so that you don't
have to repeat long command.
ctrl-u -- clears the typing before the hotkey.
ctrl-a -- takes you to the begining of the command you are currently typing.
ctrl-e -- takes you to the end of the command you are currently typing in.
esc-b -- takes you back by one word while typing a command.
ctrl-c -- kills the current command or process.
ctrl-d -- kills the shell.
ctrl-h -- deletes one letter at a time from the command you are typing in.
ctrl-z -- puts the currently running process in background, the process
can be brought back to run state by using fg command.
esc-p -- like ctrl-r lets you search through the previously given commands.
esc-. -- gives the last command you typed.

This tip generously supported by: mchulet@cabletron.com

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