Getting Variable Integer Values From Grep

i got a nasty isue here.
for my machine i want to make a checkup script to see to what wireless network i am connected to.

if i type iwconfig i get below output.
Code:

 iwconfig
wlan0     IEEE 802.11bgn  ESSID:"APqwerty"
          Mode:Managed  Frequency:2.447 GHz  Access Point: 72:6B:D3:36:29:44
          Bit Rate=54 Mb/s   Tx-Power=20 dBm
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=55/70  Signal level=-55 dBm
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:7339  Invalid misc:83573   Missed beacon:0

lo        no wireless extensions.

eth0      no wireless extensions.

With a grep awk combo i manage to narow it down.
Code:

  iwconfig | grep ESSID |awk '{ /ESSID/; print $4 }'
lo        no wireless extensions.

eth0      no wireless extensions.

ESSID:"APqwerty"

why it also shows lo and eth0 ,i dont know, but ok.

i tried several combo's on grep, awk, even cut.
i only want to catch the ESSID to where i am connected to, in this case APqwerty.
i know i am missing something, but cant find out what it is, any advice ?

I have some variables which have stored numerical values like
Quote:
A1=10 A2=20 A3=25
B1=10 B2=15 B3=12 and so on
As well as another set of variables which stored these variables like
Quote:
var1=A1 var2=A2 var3=A3
var4=B1 var5=B2 var6=B3 and so on
I have to calculated things using second set of variable.
In the script, there is line
Code:

read number

user will enter number manually, suppose 500
I have to calculate using
Code:

expr 500 \* ${$var1} / 100

and output of this multiplied by
Code:

expr $above_output \* ${$var2} /100

and output of this multiplied by
Code:

expr $above_output \* ${$var3} /100

But not able to deal with two levels of variable. The calculation will be hard when it comes for three level and four level.

Please help.

Hey all,

I just did a Debian minimal install and am using the package network-manager-gnome to manage wifi. I should also mention I'm running OpenBox. Anyway, network-manager shows up just fine in my systemtray and it lets me connect and displays that I am connected in the system tray. However, when I try to connect to a website it will just say "connecting" for a very long time before timing out. Note that my ethernet works perfectly.

If it helps, this is what shows up in iwconfig after I've "connected" to a network through network-manager:

Code:

wlan0     IEEE 802.11abgn  ESSID:"The Stack Resident Wifi"  
          Mode:Managed  Frequency:5.24 GHz  Access Point: 54:3D:37:02:A5:CC   
          Bit Rate=13 Mb/s   Tx-Power=15 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=33/70  Signal level=-77 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:154   Missed beacon:0

I've searched in many places and I couldn't find someone who had a similar problem. Any help would be awesome. Thanks!

Hi,

I am not completely new to linux.

My problem is the following:

The signal queue of my process gets filled with time.

With /proc/PID/status --> SigQ 6032/6032 i can see that the queue is full!

And my software is waiting on signals to process data. So I want to know wich signal filled my queue and I am interested to see the attached data of the signal --> sival_int or sival_ptr, I use sigwaitinfo() to read the data.

I am not sure how to ask this, sorry.

if I had a code like this

Code:

# grep -a ": " md5list.txt | cut -f2,3 -d

How can I run the command basename for each line of the output?

basename {(grep -a ": " md5list.txt | cut -f2,3 -d )}


EDIT: A little more clarity on what im doing:
I didn't realize that 'md5sums' was a link to a nice formatted page. So I copied all packages here and put them into a text file. I decided to write a script that put all of these in that format.

So basically, even though I have already ran the md5sum -c 'md5sum-list' I still want to finish this small project because I am learning a ton.

The most recent info on this card is about 10 years old.

The story is that I had an old dying PC with a vast accumulation of dust, causing sparks to fly.
I transferred the disk & wireless card across to a "known good PC" - and "amazingly" it worked.

This lasted for about a week.
OS is Xubuntu 12.04 and recommended updates of an unknown nature were applied from repositories & PPA's (not by me).

Soon after, wireless on the ancient Netgear wg311t PCI card failed.
I've tried moving it to a different slot - still does not work.
I've tried booting up from a Xubuntu 14.04.2 DVD - still does not work.
The two slots give slightly different results to the command Code:

dmesg | grep ath5k

First slot Code:

[   63.714417] ath5k 0000:05:06.0: registered as 'phy0'
[   63.733142] ath5k: phy0: failed to wakeup the MAC Chip
[   63.733482] ath5k: probe of 0000:05:06.0 failed with error -5

Second slot Code:

[   13.594859] ath5k 0000:05:08.0: PCI INT A -> Link[APC3] -> GSI 18 (level, low) -> IRQ 18
[   13.594943] ath5k 0000:05:08.0: registered as 'phy0'
[   13.606136] ath5k phy0: failed to wakeup the MAC Chip
[   13.606531] ath5k 0000:05:08.0: PCI INT A disabled
[   13.606768] ath5k: probe of 0000:05:08.0 failed with error -5

I'm prepared to buy a replacement card - so long as it is cheap!

Hey guys,

Something is puzzling me!

I saw someone use the grep in the following way and I'm not sure I understand what it does, and if there's any benefit to using it this way.

Code:

grep X.X.X.X /var/log/log.log | grep -v query

I checked the man file which confirmed that -v is relating to matching non grouping lines (which I'm not sure I fully understand either!) but I don't see any difference in the output of the above command versus the same command without the | grep -v query bit..

Why would you pipe grep into grep unless you were searching for something specific within the search results?

Does query mean something else?

Hey guys, I am a little confused about run level programs. (concerning centos)

I know when the system boots up the orders will be

bios
MBR
GRUB
kernel
init
runlevel

to my understanding - etc/init looks at /etc/inittab
then where is the run level located?
is it /etc/rc.d/rc0.d...
/etc/rc.d/rc1.d
/etc/rc.d/rc2.d
are these run level programs?

if so, what about /etc/init.d ? doesnt that also execute run level programs?

and how does it know what to start? where does it look

thanks guys just a bit confusing where what looks for what

Hi ,

Please explain what the below command means ..


Code:

if grep -c -i Y $INIFILE > /dev/null

I know what is the use of grep, it is used for finding a character or string in a file. But i could not understand the above form of grep command.

I am new to linux so this might be a simple question, but please throw some light on it.


Edited

And also please explain why they are creating a file in null in the below command

Code:

cat /dev/null > $DATA_DIR/$DATAFILE

Several of the apps are intermittently hanging and I am getting "Signal 11 error" messages. What is this error and what do I need to do about it?