RPM querry packages and there build arch

Most of the time rpm shows is the package name - version, but strips the build arch, ie. i386 or x86_64. Hence what we see are 2 similar package names and we wondering what is going on :)


$ rpm -qf /usr/bin/lsb_release
redhat-lsb-4.0-2.1.4.el5
redhat-lsb-4.0-2.1.4.el5

here is a way to see the arch use '--qf "%{n}-%{v}-%{r}-%{arch}\n"'


$ rpm -qf /usr/bin/lsb_release --qf "%{n}-%{v}-%{r}-%{arch}\n"
redhat-lsb-4.0-2.1.4.el5-x86_64
redhat-lsb-4.0-2.1.4.el5-i386

converting to world date/timezones on linux, with the humble date

Playing with dates in linux, our humble date is well equipped.

• Want the IST date, in case your host is a PDT/UTC one.

#TZ="Asia/Calcutta" date

• Want a specific date (older)

# TZ="Asia/Calcutta" date -d "2011-07-10 19:58 PDT"

Mon Jul 11 08:28:00 IST 2011

• Other way

# TZ="America/Los_Angeles" date -d "2011-07-10 7:58 IST"

Sat Jul 9 19:28:00 PDT 2011

• If you need to find all the valid country specific timezone constants :

# ls -l /usr/share/zoneinfo/{continent}/{city}

• Here is something cool you can do at your bash prompt:

PS1="[\$(TZ=\"Asia/Calcutta\" date +%D-%k:%M:%S) IST, \$(TZ=\"America/Los_Angeles\" date +%D-%k:%M:%S) PDT]"

PS1="$PS1\[\e[36m\]\u\[\e[0m\]"

PS1="$PS1@"

Shows me this

[07/12/11-17:32:24 IST, 07/12/11- 5:02:24 PDT]myname@myhost]$

lsof is magical

Here is a link, which is kind of primer for lsof, since it has examples.

Here are some examples I have come across which are interesting and cool.

kill -9 `lsof -t -c sshd +f -- /dev/md2`
I want to kill all process which connects to my sshd, and are accessing raid /dev/md2. ensures no one is connected via ssh and is using the drive. I can then safely shut down sshd.


lsof -t -c java -a -u -a +f -- /dev/md2
this is a combination of
-c command
-a and
-u userid
-a and (another and)
+f file accessing raid disk.


lsof +f -- /var/log
everything accessing

you send a HUP to all process accessing /var/log, generally daemons accessing logs
kill -HUP `lsof +f -- /var/log`


lsof -i| grep LISTEN
all that your host is listening (-i is for tcp connections)

who is connected on port 6014
lsof -i:6014

lsof -i:22 -a -u
all those connected to port 22 and having remember if you do not specify -a, it becomes an or and that would mean any thing accessed by

# lsof -i:22 -a -u *uid* | wc -l
14

# lsof -i:22 -u *uid* | wc -l
1228

remeber -t is for terse, it understands, that you only are interested in the process id.

# lsof -t -i:22 -u *uid* | wc -l
100

even thoud *uid* user was accessing tons of files etc. he is running 100 process which are the handles to all those activity.

enjoy!

Collection of links collected on monitoring/investigating memory on linux boxes

http://ktown.kde.org/~seli/memory/analysis.html
http://www.berthels.co.uk/exmap/doc.html
http://valgrind.org/docs/manual/QuickStart.html
http://virtualthreads.blogspot.com/2006/02/understanding-memory-usage-on-linux.html



http://stackoverflow.com/about
http://blekko.com/