One of the best things about Cygwin is that these commands useful for “quick and dirty” work on large chunks of text data are easy to learn, are consistent across all Unix-based OSs, have a number of options, and are quite extensive. When used in combination, they can save a lot of programming.

($ <command> <option> <inputs> is the general format for almost any of these commands. $ <command> –help shows the usage information.)

Note that all the commands below work on text files, not just any files with text content in them.  e.g. a .DOC or a .HTML contains many other headers which are also taken into account when processed by these commands.

wc: wc is short for “word count”, but it counts more than just words. It can count chars (-m), lines (-l) apart from words (-w).

uniq: When files have a large number of lines with many identical ones, uniq returns only once all lines among the input files after discarding repetitions. –c also gives the number of times each line has been repeated, –u returns only the unique lines discarding any line which has been repeated more than once, –i considers two lines non-unique if they are only differing the case.

sort: Say you have several files with numbers or words that need to be sorted. Sort can sort a concatenation of several files at once, where each line is considered a separate value to be sorted. The sorting order can be specified as in –d means dictionary-order, –f means ignore case, –n means numeric sort, –u means sort only unique lines.

grep: Short for “get regular expression”, grep can be used to search for a specific string or string pattern (called regular expression) in given text. $ grep “grep” <this-post> shows all the lines with the string “grep” in them. –c is used to count the number of occurrences, –i is used to ignore case, –v is used to invert the result.

sed: sed is used primarily to find and replace a string or string pattern from files. The most common usage is $ sed ‘s/<find-string>/<replace-with-string>/g’ which replaces all occurrences of <find-string> with <replace-with-string>.

Post from: EveryJoe

Cygwin Commands for Text Manipulation

Directory Structure
Cygwin uses the POSIX notation standard in paths. That is, instead of ‘\’ as in Windows, it uses the more convenient ‘/’ as in Unix. The web follows the same notation. For instance, take http://thatdamnpc.com/category/cygwin-unix. On the web host, one might find a directory called “category” in the main directory and a sub-directory “cygwin-unix” along with other category names in it.

‘/’, the root directory, is considered the parent directory under which all directories fall, like /usr, /bin, /lib, /tmp, /var, etc. /A/B/C/D/E/F.txt would mean a file F.txt present in E, a sub-directory of D, which is a sub-directory of C, which is a sub-directory of B, which is a sub-directory of A, which is a sub-directory of /, the root.

If you look at the contents of / (ls / or dir /) in your Cygwin terminal, you will notice a sub-directory called cygdrive. This contains all the Windows drives in it. Your C: drive can be got to through /cygdrive/c.

For convenience, we can remove this /cygdrive prefix in the following ways:

1. $ cd /
    $ mkdir c e
    $ mount c: /c
    $ mount e: /e

2. $ mount –c /

In this way your main Windows drives will be direct sub-directories of /.

PATH
Check what your path is using echo $PATH command. It should have at least the following: /usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/c/WINDOWS/
system32:/c/WINDOWS:/c/WINDOWS/System32/Wbem:/c/SysinternalsSuite

Using this path setting, we can run even those programs that we could run from the MS Command Prompt. If you have any other files which can be run from command line, add them to the path using your .profile. We’ve already seen that.

Good to go from next week.

Post from: EveryJoe

POSIX and PATH

Poderosa is the best terminal emulator for Cygwin that I have come across. It has a tabbed GUI, much like the PuTTY Connection Manager. However, in addition to the network communication protocols through which one can connect to a remote system using PuTTY, local Cygwin shells can also be opened using Poderosa. I use it mainly for the latter purpose.

Poderosa allows the user to set custom fonts and colors, keyboard shortcuts, command suggestions, etc. The “detailed preference editor” is especially useful, though not very straightforward to use. The app was built in a plug-in architecture and allows one to build custom plug-ins.

Poderosa too needs .NET Framework 2.0 preinstalled on your computer. Unlike PuTTY Connection Manager, I found Poderosa very stable. For telnet though, Poderosa gave me trouble where the PuTTY Connection Manager worked.

Poderosa, according to the website, had funding from the Japanese Govt. during 2005. Presently, its development seems to have stopped over a couple of years ago. The last release was v4.1.0 and you can get it from here.

Image Source: Poderosa on my PC.

Post from: EveryJoe

Poderosa: The Terminal Emulator

I recently discovered that there is a tabbed version of PuTTY called the PuTTY Connection Manager allowing multiple PuTTY instances in a single window.

PuTTY Connection Manager has several other features like workspace customizations, auto-login and post-login commands, Import/Export connection info to XML, and localization in French. Though the installation installs a help document, it runs as a standalone application and is easily portable.

The app crashed on a few instances while I was using it, and it takes a few seconds to start, but I find it very useful. Also, considering that it is still in version 0.7 alpha and is actively being updated, I have every hope that it will become more stable in the coming future.

The app was developed using C# and it needs Microsoft .NET Framework 2.0. Unlike PuTTY this is not open source but a freeware.

Image Source: Putty Connection Manager website.

Post from: EveryJoe

PuTTY Connection Manager for Tabbed PuTTY

Jason, celebrating his three-year anniversary at Microsoft Weblog, sees a surge in Zune’s popularity since the 30GB Zune owners started experiencing widespread failure and Microsoft subsequently updating them about its fix. He still wants to buy Zune, but do you recommend it?

Clair introduces us to a cool terminal user whom all lovers of CLI can follow on Twitter and Identi.ca, and teaches two techniques off adding watermark to your images.

Jayvee laments about the closing of Electronic Gaming Monthly and cheers the usage of Youtube by Ohio Police to solve a crime.

Milo lists 4 correct moves made by Microsoft in 2008 and reacts to 5 things that Steve wouldn’t tell about Windows 7.

Post from: EveryJoe

Tech Channel Roundup From Steve Jobs to Steve Ballmer

Cygwin loads its settings from a file called .profile present in the HOME environment variable. By default, HOME is set to /home/<username> which in Windows can be reached in C:\cygwin\home\<username> (assuming you have installed Cygwin in C:\cygwin folder).

.profile can be opened using any text editor. Here you can set colors to be displayed, prompt, history, aliases, default working directory, and any banner you may wish. The colors you choose will interfere with the colors set in your command prompt.

Below is a sample .profile.

————————————————————————————————–
# .profile

# Define some colors first:
red=’\e[0;31m'
RED='\e[1;31m'
green='\e[0;32m'
GREEN='\e[1;32m'
yellow='\e[0;33m'
YELLOW='\e[1;33m'
blue='\e[0;34m'
BLUE='\e[1;34m'
pink='\e[0;35m'
PINK='\e[1;35m'
cyan='\e[0;36m'
CYAN='\e[1;36m'
NC='\e[0m'

# Colors and Prompt
export PS1="\[\e]2;\u@\h:\w\007$green\]\u@\h:\[$pink\]\w\[$blue\]$ \[$BLUE\]“          # Word wrap of previous line.

set -o vi
export EDITOR=vi

# History
export HISTSIZE=1000
export HISTFILE=~/.bash_history
export HISTFILESIZE=1000

# Various Aliases
alias dir=’ls –color=auto’

# Working directory
cd /e/home

# Banner
echo -e “${cyan}”
echo \ \ \ \ \ #======================#
echo \ \ \ \ \ # Welcome back Sravan!\ #
echo \ \ \ \ \ #\ \ \ I missed you.\ \ \ \ \ \ #
echo \ \ \ \ \ #======================#
echo
————————————————————————————————–

The above .profile first defines some colors. One could directly use the color codes but this is more readable. Next, it sets the prompt settings. We’ll go over what the PS1 line exactly means later. The script then sets output display settings, history file settings, aliases, default working directory and banner. Comments are prefixed with a #.

You might have to tweak some color combinations in the PS1 line. I use a variant of the above .profile in combination with a command prompt with colors mainly set to a white background and a blue text as against the default black background and a white text. This is more pleasant to my eyes, giving me a white board and a blue marker feeling.

Let me know if you need further help with this. I’m not going into detail because it is off-putting to discuss too much about colors here.

Image Source: Cygwin screenshot from my PC.

Post from: EveryJoe

Customizing the Cygwin Terminal

Windows is primarily popular for its apparent user-friendliness. Unix-based OSs are chosen for their open and active communities. Windows is sufficient for ‘general purposes’ like listening to songs, playing games, making documents, sending mail, browsing the Internet. Unix-based OSs may seem more convenient for ‘geeky purposes’ like tweaking with the computer, writing programs, and pushing boundaries.

One feature that strongly separates Windows and Unix-based OSs is the shell. Windows has a command prompt from where various programs can be run using commands. It is more powerful than what most realize but is rarely used. On the contrary, users of Unix-based OSs greatly depend on their very powerful shell (which is run through a computer terminal or console) and run most programs through it.

Users forced to switch to Windows are commonly peeved by the limitations of the command prompt. Nevertheless there is an alternative to make them feel more at home: Cygwin. In fact, there are a few other alternatives, but Cygwin is what I’m very comfortable with and is also, IMHO, more exhaustive than others. Learning Cygwin is very useful even for Windows users to feel more comfortable when they ever encounter Unix-based OSs, or work in a multi-platform environment where you might have to mix Unix with Windows.

From here on, we shall regularly try to learn Cygwin, a nibble at a time. Share this news to your friends who are interested in learning UNIX or Cygwin. We’ll decide on the bite-size based on the community response.

Post from: EveryJoe

Windows, Other Operating Systems, Cygwin