Array of all possible colors in bash script

Sometime back, we had looked at using colors in bash script and here is a way to create a array of all the colors.

#!/bin/bash - 
#===============================================================================
#
#          FILE:  colorarray.sh
# 
#         USAGE:  ./colorarray.sh 
# 
#   DESCRIPTION:  
# 
#       OPTIONS:  ---
#  REQUIREMENTS:  ---
#          BUGS:  ---
#         NOTES:  ---
#        AUTHOR: Amit Agarwal (aka), amit.agarwal@roamware.com
#       COMPANY: Roamware India Pvt Ltd
#       CREATED: 16/04/12 17:24:09 IST
# Last modified: Mon Apr 16, 2012  05:39PM
#      REVISION:  ---
#===============================================================================
count=0
for i in 40m 41m 42m 43m 44m 45m 46m 47m
do
    for l in 0 1
    do
        echo -n "l=$l "
        for k in 0 1
        do
            # echo -n "k=$k "
            for j in {30..37}
            do
                carr[$count]="\033[$k;$j;$l;$i"
                echo -ne "${carr[$count]}$count \033[00m"
                ((count++))
            done
        done
        echo
    done
    echo
done

You can add this script to any script of your choice and you have all the 256 colors available to you in the script without additional coding. Happy coding.

colors in bash scripts

I have been trying to understand the color codes for bash for a pretty long time, but somehow never got time to understand this clearly. So this time around when I was writing a script to analyze some logs. I thought I will give it a go and finally understood some part of this.

So, first we will start with this script. This is taken from here.

Your own local search engine.

There are times when you would want to have a local search engine capable of indexing even pdf and doc files. So here is a solution.

You can use “Omega” and here are the instructions.

download omega from http:// xapian.org/download

yum install xapian libuuid-devel

And then make and install omega and for this you can follow the instructions.

Create index using command omindex
and then you can use quest or search.py to search or you can setup the cgi way so that you can use local browser to search.

Setup your own RFC Editor for Linux.

Well, if you are a professional who has to keep referring to RFC, then you know how good it would be to have the RFC downloaded and kept in your computer. But then unless you can search it and use and editor with it, its of not much use. So, here is something  that you can do :

Using file partially for filenames

There are some commands that take file name and there are some case where you need to give file name. But there are some cases where you want to modify the file before passing it to the command. What do you do in these case’s?

I had a file containing huge amount of data and for some testing I wanted to pass only the first few lines of the file and not the complete file.  And since the file only accepted filename and would not take any input from the STDIN so only option was to create a file with the required data in a temporary file. So, I sat back to figure out some way to do it and finally found I can use this:

Benchmarking the system/CPU performance

Have you ever wanted to have a quick check on your CPU performance. I know that lot of people will say that this is not the right way to do this, but here is something that you can use to check the CPU speed.

#!/bin/bash -
#===============================================================================
#
#          FILE:  benchmark.sh
#
#         USAGE:  ./benchmark.sh
#
#   DESCRIPTION:  Benchmark the CPU
#
#       OPTIONS:  ---
#  REQUIREMENTS:  ---
#          BUGS:  ---
#         NOTES:  ---
#        AUTHOR: Amit Agarwal (aka), amit.agarwal@roamware.com
#       COMPANY: Roamware India Pvt Ltd
#       CREATED: 09/21/2011 11:46:03 AM IST
# Last modified: Wed Sep 21, 2011  12:22PM
#      REVISION:  ---
#===============================================================================

add ()
{
    COUNTER=0
    exec 2>&1
    time=$(exec 2>&1;(time while [[  $COUNTER -lt 100000 ]]; do ((COUNTER++)) \
        ; done))
    echo "Time for 100000 additions is "$time
}	# ----------  end of function add  ----------
mul ()
{
    COUNTER=0
    test=2
    exec 2>&1
    time=$(exec 2>&1;(time while [[  $COUNTER -lt 100000 ]]; do ((COUNTER++)) \
        ; ((test=test*2));done))
    echo "Time for 100000 mul is "$time
}	# ----------  end of function add  ----------
div ()
{
    COUNTER=0
    test=1000000000000
    exec 2>&1
    time=$(exec 2>&1;(time while [[  $COUNTER -lt 100000 ]]; do ((COUNTER++)) \
        ; (( test=test/2)); done)|tr -d '\n')
    echo "Time for 100000 divisions is "${time}
}	# ----------  end of function add  ----------

time add
time mul
time div

And here is the output :

BASH Script Performace

Today 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.