code4Py | Style Unified Differences

As per recently created page, the following diff command output representing unified differences, needed to be styled;

[vagrant@localhost python]$ diff -u A B
--- A   2014-08-20 20:13:30.315009258 +0000
+++ B   2014-08-20 20:13:39.021009349 +0000
@@ -1,6 +1,9 @@
+typeset -i sum=0
+
 while read num
 do
   printf "%d " ${num}
+  sum=sum+${num}
 done <<EOF
 1
 2
@@ -9,5 +12,4 @@
 5
 EOF

-echo
-
+echo; echo "Sum: ${sum}"
[vagrant@localhost python]$

Source Code (GitHub Gist)
I have completed writing python script that will generate HTML output as follows.

<tr>
  <td>
    <span style='color: green'>typeset -i sum=0</span><br />
    <span style='color: green'></span><br />
    while read num<br />
    do<br />
      printf "%d " ${num}<br />
    <span style='color: green'>  sum=sum+${num}</span><br />
    done <<EOF<br />
    1<br />
    2
  </td>
</tr>
<tr>
  <td>
    5<br />
    EOF<br />
    <br />
    <span style='color: red'>echo </span><br />
    <span style='color: red'></span><br />
    <span style='color: green'>echo; echo "Sum: ${sum}"</span>
  </td>
</tr>

Style Output
This output tabulates the differences in N-row(s) and single-column format, if properly embedded into table element of HTML document, which could then be rendered by web browser based on CSS properties (if defined).

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code4Py | Style Context Differences

As per recently created page, the following diff command output representing context differences, needed to be styled;

[vagrant@localhost python]$ diff -c A B
*** A   2014-08-20 20:13:30.315009258 +0000
--- B   2014-08-20 20:13:39.021009349 +0000
***************
*** 1,6 ****
--- 1,9 ----
+ typeset -i sum=0
+
  while read num
  do
    printf "%d " ${num}
+   sum=sum+${num}
  done <<EOF
  1
  2
***************
*** 9,13 ****
  5
  EOF

! echo
!
--- 12,15 ----
  5
  EOF

! echo; echo "Sum: ${sum}"
[vagrant@localhost python]$

Source Code (GitHub Gist)
I have completed writing python script that will generate HTML output as follows.

<tr>
  <td>

  </td>
  <td>
    <span style='color: green'> typeset -i sum=0</span><br />
    <span style='color: green'> </span><br />
     while read num<br />
     do<br />
       printf "%d " ${num}<br />
    <span style='color: green'>   sum=sum+${num}</span><br />
     done <<EOF<br />
     1<br />
     2
  </td>
</tr>
<tr>
  <td>
     5<br />
     EOF<br />
     <br />
    <span style='color: blue'> echo </span><br />
    <span style='color: blue'> </span>
  </td>
  <td>
     5<br />
     EOF<br />
     <br />
    <span style='color: blue'> echo; echo "Sum: ${sum}"</span>
  </td>
</tr>

Style Output
This output tabulates the differences in N-row(s) and 2-column(s) format, if properly embedded into table element of HTML document, which could then be rendered by web browser based on CSS properties (if defined).

code4Nix | Extract code blocks with ease

Many times, I come across scenario, wherein I need to split given file into sections and write it into different files or process them dynamically, as and when those sections are found.

I did solve this problem, although I find it to be rather inefficient, so I though of rewriting and came up with following generic function, which could be used by anyone to work on scenarios like extract function blocks from shell/perl/python scripts, or extract diff block from git diff output, etc.

Function Specification

function fn__extrt_block {

  test $# -ne 2 && exit 1
  test -f $2 && fv_iputFile=$2 || exit 2
  fv_srchPtrn="$1"

  fv_funcWorkDir=$HOME/${0}
  mkdir -p ${fv_funcWorkDir} && cd ${fv_funcWorkDir}

  grep -n "${fv_srchPtrn}" ${fv_iputFile} | cut -d':' -f1 > outfile

This grep command helps in finding out the line number to mark the beginning of block, using which following while loop will extract separate blocks.

  while true
  do
    echo $(head -2 outfile) | read LB UB
    test ! -z ${UB} && UB=`echo ${UB} - 1 | bc`

LB and UB represents the lower and upper bound of block, i.e. beginning and ending of specific block. For instance, if the outfile has contents like this;

1:Hi Varun

15:Hi Nischal

24:Hi Team

Every iteration, reads first two lines and assigns LB to 1, UB to 15. Next line of code, decrements UB by 1, so as to mark the end of block correctly.

    echo "${LB},${UB:-\$}p" > sed_scpt
    sed -n -f sed_scpt ${fv_iputFile} > file__${LB}_${UB:-$}

Once LB and UB are set, it becomes easy to extract block from input file using sed -n, as shown above. To continue iterating, it is important to keep removing first line, after every successful iteration.

    sed '1d' outfile > outfile.n
    mv outfile.n outfile

As this is an infinite loop, it is important to break the loop, once input file is completely processed.

    test ! -s outfile && break
  done
}

Usage

Let us say, you generate diff between two git commits using following command;

$> git diff versOne versTwo > ~/output__versOne_versTwo.diff

Then, execute the earlier defined function as follows;

$> fn__extrt_block '^diff' ~/output__versOne_versTwo.diff

This will generate block-specific files, with pattern file__*

GitHub Gist Code Reference

https://gist.github.com/nvarun/9575155

Hope this helps.

taT4Nix | Setting up Git repository in Fedora 12

I have been using Git for quite sometime now, although at work place. I could explore as much as I could, by setting up local repositories only. One day, I thought of cloning one of the repositories hosted at GitHub. However, I could not, possibly due to restrictions in place by System Administrator (I guess).

Setup GitHub Account and Installing Git

Now, to get more out of GitHub and explore further, I need a GitHub account and Linux OS. So I got started by setting up my account at GitHub and created repository, PrayogShala.

Recently, I had installed Fedora 12 (64 Bit) as Guest OS (via Virtual Box). So, I started the Virtual Machine and logged in with user account [nvarun] (created while installing the Guest OS) and executed steps as follows.

To begin contributing to repository at GitHub, one should install Git first and to do that, open up Terminal Desktop Application and refer yum steps in the reference guide.

Once dependencies are installed/updated, execute following command;

$> sudo yum install git

Once completed, find out the installed version of Git;

$> git --version
git version 1.7.2.3

Clone Repository

After installing Git, I cloned the repository earlier created on GitHub as follows;

$> git clone https://github.com/nvarun/PrayogShala.git PrayogShala

Then, based on my experiences at work place, I added useful git aliases in $HOME/.profile and started added/updating files in the repository. The interesting thing to notice, that all the changes I make, affects repository locally. To push the changes to remote location, i.e. the repository hosted at GitHub, execute following command;

$> git push origin master

Once you do that, the Terminal prompts for username and password of GitHub account. If validated with success, the changes are pushed successfully onto GitHub.

taT4Nix | Useful Git Aliases

Couple of months back, I mentioned that I started using Git at workplace, thanks to my colleague. So far, I have been creating local repositories at workplace and in the process, spent lot of time exploring as much as I can.

This made me use the command line extensively and I ended up writing 3-letter aliases as follows, which helped saving lot of time.

alias gbr='git branch'
alias gco='git checkout'
alias gci='git commit'
alias gcm='git checkout master'
alias glo='git log --oneline'
alias gst='git status'

This would help, only if you are using command-line interfaces, on Linux/Unix Server.