Here is a nice link on BASH History Expansion. There are lot of examples in this page and some of them might be quite useful. But here are my list of favourites:
!!
This is probably the most used one by me. This will repeat the last command. And this works even in conjunction with other commands like
Continue readingHere are one sql script that I found some time back. This will be listing the top 5 SQL queries in Oracle.
SET linesize 300
SET PAGESIZE 200
select *
from
(select sql_text,
sql_id,
elapsed_time,
cpu_time,
user_io_wait_time
from sys.v_$sqlarea
order by 5 desc)
where rownum < 6;
quit;
You would have used top at some point of time. Did you not wish that instead of just the processes it list all the vital statistics of the system as a whole. How good it would be to see the Memory, Net, Processes and Disk usage on the same screen. Well then you should take a look at glances. Here is how it looks:
][1]For using this tool, here is what you need to do :
Continue readingToday we will look at some bash code snippests and the performance issues. Lets first look at the problem and the implemented solution:
Problem: We needed to log the output of the ps command for all the process’s. This was required to be done on per minute basis and the output was required in comma separated files. So, here is what was implemented:
pslog=`ps -e -opid,ppid,user,nlwp,pmem,vsz,rss,s,time,stime,pri,nice,pcp:u,args|grep -v PID|sort -r -k 13,13`
OLD_IFS=$IFS
IFS=$'\n'
logarr=( $pslog )
for LOGLINE in ${logarr[@]}
do
LOGLINE=`echo $LOGLINE|awk '{OFS=",";print $1,$2,$3,$4,$5,$6,$7,:$8,$9,$10,$11,$12,$13,$14}'`
echo $LOGLINE >> output
done
IFS=$OLD_IFS
This was working well and there were no issues. But suddenly we started seeing issues with the reported CPU usages. We would see that whenever this script was running the CPU usage was high, specially if there were too many process’s/thread’s on the system during that time. This code was definitely part of a very large code base, and at this point of time we did not know what was causing the issues.
Continue readingI was working on some scripts and the changes that I was making in the scripts was very dynamic, which I did want to keep backing up in the version control system. But for the peace of my mind, I wanted to keep a copy of the scripts, whenever it was in working state.
Since I had multiple files, so it would make more sense to have a script that could copy all the files in the current directory to “old” directory without over-writing the existing files. So, I wrote a script that would postfix the files with a number. With this approach, finally what I had was the following:
Continue readingHere is one of the scripts that I found on the net while searching for something … Note the URL for the script in the Description.
#!/bin/bash - #=============================================================================== # # FILE: linux_hw.sh # # USAGE: ./linux_hw.sh # # DESCRIPTION: http://www.howtogeek.com/howto/solaris/get-the-processor-type-on-solaris/ # # OPTIONS: --- # REQUIREMENTS: --- # BUGS: --- # NOTES: --- # AUTHOR: Amit Agarwal (aka), amit.agarwal@roamware.com # COMPANY: Roamware India Pvt Ltd # CREATED: 09/13/2011 03:57:34 PM IST # Last modified: Sun Oct 30, 2011 04:59PM # REVISION: --- #=============================================================================== function linux_hw_CPU { typeset num=0 typeset name="" typeset cores="" name="$( cat /proc/cpuinfo | awk -F: ' /vendor_id/ { vendor=$2 } /model name/ { model=$2 } /cpu MHz/ { if( model ~ "Hz" ) {speed=""} else { speed=$2? MHz" }; print vendor, model, speed; } ' | tail -1 )" num=$(if [ -r /proc/vmware/cpuinfo ]; then awk '/pcpu/ { print NF-1 }' /proc/vmware/cpuinfo; else cat /proc/cpuinfo | grep processor| wc -l; fi) # ESX: mas info sobre logical/cores/packages if [ -r /proc/vmware/sched/ncpus ] then cores=$( echo $( cat /proc/vmware/sched/ncpus ) ) fi echo $num $( echo "$name ($cores)" | enclose ) } function enclose { tr -s " " | sed -e "s/^/\"/; s/$/\"/; s/\"\ /\"/; s/\ \"/\"/" } function linux_hw_CPU { typeset num=0 typeset name="" typeset cores="" name="$( cat /proc/cpuinfo | awk -F: ' /vendor_id/ { vendor=$2 } /model name/ { model=$2 } /cpu MHz/ { if( model ~ "Hz" ) {speed=""} else { speed=$2" MHz" }; print vendor, model, speed; } ' | tail -1 )" num=$( if [ -r /proc/vmware/cpuinfo ] then awk '/pcpu/ { print NF-1 }' /proc/vmware/cpuinfo else cat /proc/cpuinfo | grep processor| wc -l fi ) if grep -q "physical id" /proc/cpuinfo || grep "siblings" /proc/cpuinfo then chip_count=$( grep "physical id" /proc/cpuinfo | sort -u | wc -l ) chip_core=$( grep "siblings" /proc/cpuinfo | tail -1 | cut -d: -f2 ) cores="($chip_count chips x $chip_core cores)" fi # Blades HP con if [ -x /sbin/hpasmcli ] then chip_name=$( /sbin/hpasmcli -s "SHOW SERVER" | grep "Name" | head -1 | cut -d: -f2 ) chip_speed=$( /sbin/hpasmcli -s "SHOW SERVER" | grep "Speed" | head -1 | cut -d: -f2 ) chip_core=$( /sbin/hpasmcli -s "SHOW SERVER" | grep "Core" | head -1 | cut -d: -f2 ) fi # ESX: mas info sobre logical/cores/packages if [ -r /proc/vmware/sched/ncpus ] then cores="($( echo $( cat /proc/vmware/sched/ncpus ) ))" fi # Linux Itanium IA64 if grep -q -i itanium /proc/cpuinfo then name="$( grep "vendor" /proc/cpuinfo | cut -d: -f2- | tail -1 ) $( grep "arch " /proc/cpuinfo | cut -d: -f2- | tail -1 ) $( grep "family" /proc/cpuinfo | cut -d: -f2- | tail -1 ) $( grep "cpu MHz" /proc/cpuinfo | cut -d: -f2- | cut -d. -f1 | tail -1 ) Mhz" chip_count=$( grep "physical id" /proc/cpuinfo | sort -u | wc -l ) chip_core=$( grep "siblings" /proc/cpuinfo | tail -1 | cut -d: -f2 ) cores="($chip_count chips x $chip_core cores)" fi echo $num $( echo "$name $cores" | enclose ) } linux_hw_CPU
Last time we got ourselves some conkyrc files from the ubuntu forums. But that scripts gets the files only from the First page of the thread. Lets extend this further and get the script to get all the conkyrc files.
There are some 1048 pages in the thread, I am showing pages 1 to 3 but you can change 3 to whatever number you want 🙂
count=0
for i in {1..3}
do
>.test
>conkyrc
echo "Getting page $i"
curl http://ubuntuforums.org/showthread.php?t=281865\&page=$i |\\
sed -n '// d'|\
sed 's##\n-----------------------------------\n\n\n#' \
>conkyrc
dos2unix conkyrc
cp conkyrc .test
while [ $(wc -l .test|sed 's/[^0-9]//g') != 0 ]
do
sed -n '1,/------------------------/ p' .test|sed '$d' >conkyrc.$count
diff .test conkyrc.$count |sed 's/^<.//'|sed '1, /---------------------/ d;2d'>.test
((count++))
done
echo "Files so far are : $count"
done