nixCraft

hi,

what is the use of sed command and i had seen one command like

sed '
s/ \([0-9]\)/,\1/
s/\([0-9]\) /\1,/
' test | sort -k1,3

here i am getting bit confusion with frontslash and backslah why they but / and \ again and again. plz explain to me . i am new learner to shell script

sed is for editing file without using text editor such as vi.
sed '/foo/s//bar/g' data.txt
above command is nothing but find and replace operation according to given regex. it will find word occurrence of word foo and replace with bar from data.txt file. \ use to disable special regex character. In this case it will disable ( and ), which is use to match entire word/regex. special escapes \1 refer to the corresponding matching sub expressions from first regex.

If you have sample input file just paste it so that I can explain it better.

__________________
Vivek | My personal blog
Linux Evangelist
Play hard stay cool

I just just wanted to share a perfect example of using the sed command...

I am a multimedia and web-designer and often have to change multiple items throughout websites. Long story short, one of my clients needed their e-mail address's changed throughout their ENTIRE site. The site is fairly large, with roughly 50 pages or so (greenhouse with a page for all varieties of plant.

By using the sed command, I was able to search the ENTIRE site and replace the old e-mail address's with the new one. If I were to have to opened each .html file in nano I would have shot myself...This turned a lengthy job into a 2 min project.

FYI.
If you are planning on using any of the illegal characters in the sed command, make sure to use the '\' prior to the character itself.

ie. #: sed 's/info@youroldaddress\.com/info@yournewservice\.st\.com/g' .html

Hope this sheds some light on ONE of it's MANY, MANY uses...and hopefully if your in the same situation, helps you out!

Enjoy,
Jimmi
jarhed