Adventures of a Software Engineer

Tag: linux

  • Recursively GREP for specific content

    nohup  egrep -rnw '=\s112'  --include=*.java ./ 2>&1 | tee ~/112-audit-nick.txt

  • Run MD5 check sum against all files in a directory

    Couple snippets that allow us to run checksum and get unique md5 checksums.

    This is two step process. First, we obtain our md5 checksum for all files

    find -type f -exec md5sum "{}" + > /opt/checklist.chk

    This produces file with following contents

    71cc452a8ac5a27c32a83e6a0909e7ae  ./PID_190_7344_0_47710322.tif6712032974632727465.tiff
71cc452a8ac5a27c32a83e6a0909e7ae  ./PID_190_7344_0_47710322.tif174464329785828524.tiff
71cc452a8ac5a27c32a83e6a0909e7ae  ./PID_190_7344_0_47710322.tif6775939766281585264.tiff
71cc452a8ac5a27c32a83e6a0909e7ae  ./PID_190_7344_0_47710322.tif7205305688614612348.tiff
71cc452a8ac5a27c32a83e6a0909e7ae  ./PID_190_7344_0_47710322.tif3909999865608008175.tiff

    Next we parse and get only unique checksums.

    cat  /opt/checklist.chk | awk '{split($0, a, " "); if(!seen[a[1]]++) print a[1]}'

    This produces our distinct checksums

    71cc452a8ac5a27c32a83e6a0909e7ae

  • Configuring Java JDK on Ubuntu

    This is an easy way to configure java on a linux box, all this information is available online.

    First we need to obtain the build.

    sudo wget http://192.168.201.47:8000/jdk-7u75-linux-x64.gz

    Extract from tar

     sudo tar xzvf  jdk-7u75-linux-x64.gz

    Create symbolic link so we can later update the version

    sudo ln -s /opt/jdk1.7.0_75/ /opt/java

    we edit the /etc/profile and add following two lines

    export JAVA_HOME=/opt/java
export PATH=$JAVA_HOME/bin:$PATH

    finally we ‘source’ the file

    source /etc/profile

    At this point you should be ready to go, we can verify this by executing

    java -version

  • Grepping for multiple strings in a file

    We will use egrep which accepts a regular expression to grep for multiple strings.

    tail -f localhost_access_log.txt | egrep "\" 404|\" 500"

    Here our example looks at logs to see if we got 404 or 500 request.

     "GET /favicon.ico HTTP/1.1" 404 973
 "GET /login.html  HTTP/1.1" 500 1230
 "GET /favicon.ico HTTP/1.1" 404 973

  • Apache 408 Connection timedout

    nohup tail -f access.log | grep ‘408’ –line-buffered | awk ‘{split($0,a,” “); print a[1]; fflush()}’ | tee -a bad-408.txt

  • Starting jetty via command line an nohup

    Somehow I am getting problems starting Jetty via 

    service jetty start

    We will be using unix command called nohup
    “Nohup is a unix command, used to start another program, in such a way that it does not terminate when the parent process is terminated.”

    I have opted out for using this

    nohup java -jar start.jar -Djetty.port=8085

    while this works it shown an message

    nohup: ignoring input and appending output to `nohup.out'

    to fix that up we need to redirect in put and output to /dev/null

     nohup java -jar start.jar -Djetty.port=8085  /dev/null &