[SOLVED] Sed with AND operation

subashinik · 06-24-2010, 12:11 AM

Hello All,

Need your help on writing a sed oneliner

Let'say if I have a Txt file with following lines

Set pin1 = 0
set pin2 = 1
set pin3 = 0 ;

I want to add ";" at the end for those lines Which starts with set infront and doesn't end with ; , What would be the correpsonding sed one liner command for that.??

My Final op should look .like
Set pin1 = 0 ;
set pin2 = 1 ;
set pin3 = 0 ;

( Basically I don't know How to add AND operation in the Sed command to combine the 2 conditions of lines starting with set and doesn't end with ; ..? Thanks for your help !

Tinkster · 06-24-2010, 12:20 AM

Hi, welcome to LQ!

Not so much a sed as a regex question...

Code:

sed -r 's/^([Ss]et.*)[^;]$/\1 ;/' sed_and
Set pin1 = 0 ;
set pin2 = 1 ;
set pin3 = 0 ;

If you're unsure how the regex works - please ask.

Cheers,
Tink

vikas027 · 06-24-2010, 01:51 AM

I have another solution, although not the best one

Suppose you have a file abc.txt

Code:

[linux1@HMLINUX1 abc]$ cat abc.txt
Set pin1 = 0
pe pin1 = 0
set pin2 = 1
ge pin1 = 0
set pin3 = 0

Then, this code should work

Code:

cat abc.txt  | grep -ni set | awk -F ":" '{print $1}' > tmp
for i in `cat tmp`; do sed -i $i's/.*/& \;/' abc.txt; done;

Now ,
[linux1@HMLINUX1 abc]$ cat abc.txt

Code:

Set pin1 = 0 ;
pe pin1 = 0
set pin2 = 1 ;
ge pin1 = 0
set pin3 = 0 ;

grail · 06-24-2010, 02:10 AM

hmmm ... one would think if you are going to use awk just use it instead of going the long way:

Code:

awk '/[Ss]et.*[^;]$/{$0=$0";"}1' file

syg00 · 06-24-2010, 02:15 AM

Let's hope there are no trailing whitespaces on any of those lines ...

vikas027 · 06-24-2010, 02:23 AM

Quote:

Originally Posted by grail

hmmm ... one would think if you are going to use awk just use it instead of going the long way:

Code:

awk '/[Ss]et.*[^;]$/{$0=$0";"}1' file

Nice Grail, but what are is this for [^;]$, it is working without this also.
And what does 1 represents at last.

Code:

 
[linux1@HMLINUX1 abc]$ cat abc.txt
Set pin1 = 0
pe pin1 = 0
set pin2 = 1
ge pin1 = 0
set pin3 = 0
[linux1@HMLINUX1 abc]$
[linux1@HMLINUX1 abc]$ awk '/[Ss]et.*/{$0=$0";"}1' abc.txt
Set pin1 = 0;
pe pin1 = 0
set pin2 = 1;
ge pin1 = 0
set pin3 = 0;
[linux1@HMLINUX1 abc]$

grail · 06-24-2010, 02:29 AM

Quote:

Nice Grail, but what are is this for [^;]$, it is working without this also.

If you read the OPs original post he shows that some lines may already have semicolon at the end, therefore [^;]$ is required to test that one does not exist.

Quote:

And what does 1 represents at last.

awk's default action is to print on any true value which is any non-zero value, hence 1

schneidz · 06-24-2010, 03:15 PM

is that vhdl ?;
what micro-controller are you working on ?

Tinkster · 06-24-2010, 03:42 PM

Quote:

Originally Posted by vikas027

I have another solution, although not the best one

Suppose you have a file abc.txt

Code:

[linux1@HMLINUX1 abc]$ cat abc.txt
Set pin1 = 0
pe pin1 = 0
set pin2 = 1
ge pin1 = 0
set pin3 = 0

Then, this code should work

Code:

cat abc.txt  | grep -ni set | awk -F ":" '{print $1}' > tmp
for i in `cat tmp`; do sed -i $i's/.*/& \;/' abc.txt; done;

Now ,
[linux1@HMLINUX1 abc]$ cat abc.txt

Code:

Set pin1 = 0 ;
pe pin1 = 0
set pin2 = 1 ;
ge pin1 = 0
set pin3 = 0 ;

"Not the best" is a slight understatement ;}

You use cat & grep unnecessarily, and then a loop for no
good reason on top of that.

Cheers,
Tink

subashinik · 06-26-2010, 07:27 PM

Hello every one.

Thanks to all for you reply.Really helped me lot! This is my first thread in this site And I am glad that I received so many replies

Again Thanks for your time !

Subashinik

Tinkster · 06-27-2010, 10:21 PM

Here's your explanation:

Code:

sed -r 's/^([Ss]et.*)[^;]$/\1 ;/'

Piece by piece:

Code:

-r
put send into enhanced regex mode

Code:

s/
start search & replace operation

Code:

^
Beginning of line

Code:

(
Begin a "back reference hold"

Code:

[Ss]et.*)
a word set starting with S or s, followed
by anything, ")" closes the "(" to remember
the match.

Code:

[^;]$
Carry the match on from the remembered part if
the last character before the line end is not a
; ....

Code:

/\1 ;/
replace the matched string with what
was remembered, a space and a semicolon

subashinik · 06-29-2010, 12:24 AM

Hello Tink,

Thanks a lot for your explanations.

But this command sed -r 's/^([Ss]et.*)[^;]$/\1 ;/' <filename> adds ";" at the end of those lines which already has ";" at the end.

Do we need to add up ! at [^;]$ ..? I tried out but it doesn't work ..?

Sorry I am not good in Sed, just trying to pick up things

Thanks
Suba

grail · 06-29-2010, 02:34 AM

Hi Suba

You sure you copied/typed it correctly? What you are saying does not happen to me, although I do have a separate issue with the current sed command.

Quote:

Do we need to add up ! at [^;]$ ..? I tried out but it doesn't work ..?

If you re-read Tink's explanation you will see that "[^;]" already means not;

The issue i have when running the sed is that it removes the last character on the lines without a semicolon, ie:

Code:

#inputfile
Set pin1 = 0
set pin1 = 0
set pin1 = 0;

#output after current command
Set pin1 =  ;
set pin1 =  ;
set pin1 = 0;

As you can see the first two lines are now missing there zeroes. The following seems to remedy this:

Code:

sed -r 's/^([Ss]et.*[^;]$)/\1 ;/' <filename>

syg00 · 06-29-2010, 03:55 AM

Quote:

Originally Posted by subashinik

But this command sed -r 's/^([Ss]et.*)[^;]$/\1 ;/' <filename> adds ";" at the end of those lines which already has ";" at the end.

That will happen if the semicolon is not actually the last character - see my previous post above.

subashinik · 06-30-2010, 04:13 AM

Thanks SYg00 & grail ,

Got ur point !.
Yes , Shouldn't have any trailing whitespaces on any of those lines

Thanks to all for your time !

Btw, I am working on ASIC CHIP level verification ! And trying to learn more on scripting/Programming !

With regards
Suba