Tag Archives: Linux

Broadcom Wireless en Linux

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At work I have a Dell laptop with a Broadcom BCM94311MCG wireless card:

# lspci
...
0b:00.0 Network controller: Broadcom Corporation BCM94311MCG wlan mini-PCI (rev 01)
...
# lspci -n
...
0b:00.0 0280: 14e4:4311 (rev 01)
...

The drivers that Ubuntu installs by default were giving me lots of headaches depending on the network’s access point: on some of them the card worked OK; on some others I kept loosing the connection every few minutes, or I couldn’t connect at all. I never found out if the problem was the encryption algorithm in use, or the wifi a/b/g/whatever protocol. Bottom line is the driver worked on some networks but didn’t on some others.

A co-worker told me he had the same problem until he switched to the ndiswrapper driver, so reluctantly I tried it. It work great. :)
More info here:

Shell-script: timestamp

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A one-liner function that, when piped with the output of another command, prepends each line of that command’s output with a timestamp.

Very useful with commands that output a series of lines periodically but without a timestamp (like vmstat), so that you can’t just send their output to a file and go back to it later without a timeframe.

$ function timestamp { while read l; do d=`date +%H:%M:%S`; echo -e "$d $l"; done; }


$ vmstat 1 | timestamp

12:17:03 procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
12:17:03 r  b   swpd   free   buff  cache   si   so    bi    bo   in cs us sy id wa
12:17:03 1  0      4  16740  42816 395164    0    0     6     5  174 11  3  1 96  0
12:17:04 0  0      4  16656  42816 395184    0    0     0     0  393 510  1  1 98  0
12:17:05 0  0      4  16656  42816 395184    0    0     0     0  391 781  2  1 98  0
12:17:06 1  0      4  16656  42824 395176    0    0     0    84  462 976  3  1 95  0
12:17:07 0  0      4  16656  42824 395184    0    0     0     0  433 1545 11  3 86  0
12:17:08 0  0      4  16656  42824 395184    0    0     0     0  356 807  1  2 97  0

ifstat

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ifstat is like some kind of vmstat for network interfaces. Every X seconds, it prints two columns per network interface monitoring the input and output bandwidth.

Quite useful when you need to diagnose a slow network, identify bottlenecks, monitor bandwidth consumption, etc. When invoked with the -t parameter it adds a timestamp on each line, very important if you plan to left it running for hours dumping its output to a file.

# ifstat -t

  Time            eth0               eth1
HH:MM:SS   KB/s in  KB/s out   KB/s in  KB/s out
12:40:25      0.05      0.19      0.00      0.00
12:40:26      0.26      0.24      0.00      0.00
12:40:27      6.87     30.14      0.00      0.00
12:40:28      0.17      0.26      0.00      0.00
12:40:29      0.05      0.22      0.00      0.00
12:40:30      0.05      0.14      0.00      0.00
12:40:31      0.05      0.14      0.00      0.00
12:40:32      0.29      0.38      0.00      0.00
12:40:33      0.29      0.38      0.00      0.00
12:40:34      0.13      0.22      0.00      0.00
12:40:35      2.85      8.70      0.00      0.00
12:40:36      9.01     38.84      0.00      0.00
12:40:37      0.55      0.24      0.00      0.00
12:40:38      0.05      0.14      0.00      0.00

Command Line

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I start here a new section on my blog, Command Line (feed), where I will comment on UNIX commands (Linux and MacOS X mainly) that I find useful on my daily work. The articles will range from a very obscure command that I didn’t knew of until some day I needed something like it and found it and saved my day, new or creative ways to use old commands, or small shell-scripts that can make your life easier.

Unless otherwise specified, all these commands are just an “aptitude install” away on Debian and derivate distros (on Ubuntu they may be on universe or multiverse). For RedHat, CentOS, etc. there’s a good chance that you’ll find RPM packages on Dag Wieërs’ repository.

So, without further addo, the first command on the next entry. :)

Servidor VNC para MacOS X

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MacOS X comes with a VNC server, but it has problems: you can’t access it depending on what client version you’re using, and it seems to work only on full-quality mode (32bit color?), so it’s slow like hell.

An alternative is installing the marvelous Vine Server,which on its 3.0 release brings full client/server clipboard integration and works like a charm with any Linux VNC client, fast and without problems.