[SOLVED] Bash How to delete only one line from a file

wizard211990 · 04-09-2011, 09:45 AM

Hi, i have a big problem.

I would like to delete a single line from a file that contains many lines passing through the same values as the two parameters. Again, I would like to delete a single line and not all those that contain parameters. How can I make bash?

MTK358 · 04-09-2011, 09:47 AM

Quote:

Originally Posted by wizard211990

Hi, i have a big problem.

I would like to delete a single line from a file that contains many lines passing through the same values as the two parameters. Again, I would like to delete a single line and not all those that contain parameters. How can I make bash?

So you want a script that takes two parameters, and deletes the lines from a file that do not contain both of the strings that were passed as parameters?

wizard211990 · 04-09-2011, 09:53 AM

No, I want to delete one line among all those who have those parameters.

For Example

1 parameter: Queen 2 parameter: News of the World

Queen News of the World
Beatles Revolver
Queen News of the World
....
...
I want to delete only the first Queen News of the World but not the last

wizard211990 · 04-09-2011, 10:18 AM

I have try with awk, sed grep but nothing...Help Me...

MTK358 · 04-09-2011, 10:20 AM

So delete the first line that has both strings?

colucix · 04-09-2011, 10:22 AM

Here is an awk solution:

Code:

$ p1="Queen"
$ p2="News of the World"
$ awk -v p1="$p1" -v p2="$p2" '{ if ( $0 ~ p1 && $0 ~ p2 ) { if ( c == 1 ) print; c = 1 } else print }' file
Beatles Revolver
Queen News of the World

wizard211990 · 04-09-2011, 11:13 AM

Thanks a lot.
One last thing. I saw that it is case sensitive.
Is there a way to get it case insensitive?

wizard211990 · 04-09-2011, 11:18 AM

Quote:

Originally Posted by MTK358

So delete the first line that has both strings?

Yes, exactly.

colucix · 04-09-2011, 01:12 PM

Quote:

Originally Posted by wizard211990

One last thing. I saw that it is case sensitive.
Is there a way to get it case insensitive?

In GNU awk you can set the internal variable IGNORECASE to a non-zero value (that is true). Example:

Code:

awk -v p1="$p1" -v p2="$p2" 'BEGIN{ IGNORECASE = 1 }{ if ( $0 ~ p1 && $0 ~ p2 ) { if ( c == 1 ) print; c = 1 } else print }' file

More details in the GNU awk manual: http://www.gnu.org/software/gawk/man...02dsensitivity

crts · 04-09-2011, 05:44 PM

Hi,

if I understood correctly then there can be also an arbitrary amount of characters between the patterns and the order of the patterns does not matter, right? So these first lines would also be deleted if we use the parameters from your previous post:

Code:

Queen has News of the World  <-- delete if first occurence
News of the World Queen      <-- delete if first occurence

Here is how you can do it with sed:

Code:

p1=queen
p2='news of the world'
sed -r "/${p1}.*${p2}|${p2}.*${p1}/I {x;/^$/d}" file

wizard211990 · 04-10-2011, 02:51 AM

Yes, your script adds the ability to vary the order, but deletes all entries and not just one.

jschiwal · 04-10-2011, 03:04 AM

I think adding ;q inside the block will stop processing the file after changing the first occurrence.
{x;/^$/d;q}

colucix · 04-10-2011, 03:11 AM

Actually it exchanges the occurrences (each of them is replaced by the previous one). Example:

Code:

$ cat file
Something Here
Queen News of the World 1
Beatles Revolver
Queen News of the World 2
Something There
Queen News of the World 3
Goofy
Queen News of the World 4
Queen News of the World 5
Stop Now
$ sed -r "/${p1}.*${p2}|${p2}.*${p1}/I {x;/^$/d}" file
Something Here
Beatles Revolver
Queen News of the World 1
Something There
Queen News of the World 2
Goofy
Queen News of the World 3
Queen News of the World 4
Stop Now

colucix · 04-10-2011, 03:15 AM

Quote:

Originally Posted by jschiwal

I think adding ;q inside the block will stop processing the file after changing the first occurrence.
{x;/^$/d;q}

Doesn't this stop processing the rest of the file?

Code:

$ cat file
Something Here
Queen News of the World 1
Beatles Revolver
Queen News of the World 2
Something There
Queen News of the World 3
Goofy
Queen News of the World 4
Queen News of the World 5
Stop Now
$ sed -r "/${p1}.*${p2}|${p2}.*${p1}/I {x;/^$/d;q}" file
Something Here
Beatles Revolver
Queen News of the World 1

wizard211990 · 04-10-2011, 03:37 AM

yes, it works. Ubuntu no problem, but on the Mac of my friend has a problem. But it's ok