Unix and Linux Tips

Rabu, 30 Juni 2010

Unix Tip: BOURNE SHELL PSEUDO HASH TABLES

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3067 - June 30, 2010

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

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BOURNE SHELL PSEUDO HASH TABLES

The best way to explain this
is with an example:

You may want to write a simple
script that launches an xterm
window with different color
options. Pseudo hash tables in
bourne shell.

$ xwindow MidnightBlue

An easy way to this is by first
listing the supported colors in
the script (pseudo hash table):

DarkSlateGrey="#2f4f4f"
DimGrey="#696969"
MidnightBlue="#191970"
NavyBlue="#000080"

Next, simply grab the hex color
code by using the following
command:

BGColor=`eval echo $"$(echo $1)"`

"$(echo $1)" evaluates to "MidnightBlue" and
`eval echo $MidnightBlue evaluates to "#191970".

Simply launch the xterm window
using $BGColor as the background
color:

xterm -bg="$BGColor" &

This method for extracting pseudo hash
values may be used for NIS map files,
file date stamps, GUI colors, etc.

This tip generously supported by: Jasper.Silvis@PHL.Boeing.com

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Selasa, 29 Juni 2010

Unix Tip: BE A GURU - RTFM

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3066 - June 29, 2010

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

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BE A GURU - RTFM

The best way, is to learn
to be the best Unix Guru is
take the time to RTFM. Do
not always depend on someone
else to be there with the
knowledge.

DON'T BE LAZY!

By the Way, for those that
don't know by now.

RTFM = READ THE F^CKING MANUAL

Unix Guru Universe - www.ugu.com - tips@ugu.com - Copyright 1994-2001
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Senin, 28 Juni 2010

Unix Tip: ONE STEP AT A TIME WITH !!

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3065 - June 28, 2010

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

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ONE STEP AT A TIME WITH !!

For example using C shell I want
to edit a handful of files that
contain the string "ProcessInput"
in my current directory.

Step 1:
Find the files which uses "ProcessInput"

% grep "ProcessInput" *.c
a.c:ProcessInput ( int a )
b.c:Description : ProcessInput is used to process the input
given by the user
b.c:Call ProcessInput to perform ...
c.c:val = ProcessInput(2) ;
c.c:val = ProcessInput(3) ;

Step 2:
Extract the filenames on the left.
$!! | awk -F: '{print $1}'
a.c
b.c
b.c
c.c
c.c

step 3:
Remove the duplicates
!! | sort -u

Step 4:
Now edit it !
vi `!!`

which runs vi `grep "ProcessInput" *.c | awk -F: '{print $1}'
| sort -u`

This tip generously supported by: desikann@future.futsoft.com

Unix Guru Universe - www.ugu.com - tips@ugu.com - Copyright 1994-2001
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Minggu, 27 Juni 2010

Unix Tip: PRINTING WITH NO SPACE

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3064 - June 27, 2010

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

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PRINTING WITH NO SPACE

Sometimes there isn't enough space
in the spooling directory to print
a large file. This isn't the case
so much anymore since disk drives
are so large now.

If the file fills up the spooling
directory use and you are using
BSD "lpr" then you can pass it
the -s option.

This will create a symlink to the
file instead of coping it.

"lp" creates a symlink by default.
You can use the -c options to
force it to copy the file instead,
if needed.

Some flavors differ, check yours.

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Sabtu, 26 Juni 2010

Unix Tip: To grab all hidden files

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UNIX GURU UNIVERSE
UNIX HOT TIP

Unix Tip 3063 - June 26, 2010

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

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To grab all hidden files

A safe way of grabbing all "hidden"
files is to use '.??*' rather than
'.*' since this will only match 3
or more characters. Admittedly,
this will miss any hidden files
that are only a single character
after the ., but it will always
miss '.' & '..', which is probably
more important...

We can use .[a-zA-Z0-9]* to grab
all hidden files other
than . and .. we will not get
hidden files which dont have any
alphanumeric character following
the first '.' - can someone tell
how to go about this

This tip generously supported by: muraliaj@synopsys.com

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