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linux grep or awk command - how to search for string + execute

Hi all,
First time poster, and really hoping you'd be able to help me, as I'm stuck & hope Im posting this in right forum.

let's assume that I already have a file created. This file creation comes from the execution of a command. Contents of the file will be up to 4 different lines looking something like this:

LUN Path: servernam:/vol/server_xx_t1_01_223_04/mssql01/server_StorageSystemLevel100.lun

LUN Path: servernam:/vol/server_xx_t1_01_225_04/mssql01/server_StorageSystemLevel100.lun

LUN Path: servernam:/vol/server_xx_t1_01_226_04/mssql01/server_StorageSystemLevel100.lun

LUN Path: servernam:/vol/server_xx_t1_01_228_04/mssql01/server_StorageSystemLevel100.lun

My question is:
How am I able to pipe, awk or whatever method, thus being able to use the "2nd string of the file", ie " servernam:/vol/serverxxxx",

and run a command like, for example

rm servernam:/vol/server_xx_t1_01_228_04/mssql01/server_StorageSystemLevel100.lun

so basically filtering for the right string and execute a command against it. Note that I would need to do the same execution command against all 4 different strings. a script example / experiences or even better all from the shell command line, would be muchly appreciated.

cheers

Hi and welcome to LinuxQuestions! If you want to execute a command over all the lines in the text file, you basically need a loop fed with the content of the file:

Code:

while read line

do

  some stuff here

done < filename

To pass the extracted field to the command you need command substitution, that is:

Code:

while read line

do

  echo rm $(echo "$line" | awk '{print $3}')

done < filename

In your example the field is the 3rd, not the 2nd. In any case I put an echo statement in front of the rm command for testing purposes so that you can check the resulting commands before actually executing them. Hope this helps.

Also you could do away with and do it all in bash:

Code:

while read _ _ line

do

  echo rm "$line"

done < filename

Or do it all in awk (calling bash to execute the rm command):

Code:

awk '{ print ("echo rm " $3) | "/bin/bash" }' filename

@colucix - you probably already know but just thought I would mention that if you move the pipe to just after print it will make your current shell execute the commands :)

Code:

awk '{print | "echo rm "$3"}' filename

@grail: actually I always forget about all the print variants and their subtle differences. Thanks for that. Just a little correction to your code (you wrote an extra " after $3):

Code:

awk '{ print | "echo rm " $3 }' filename

thanks.. but a couple more questions

Hi again,

many thanks for the answers which have helped immensely , but I'd like to be clear and hopefully make what I gotta do easier..hope you can still assist..

my "raw file" ( not the one I mentioned before, has lots of info, so what I'd like to do is actually grep the

LUN Path:

the information that I need is indeed on the 3rd slot, so would like to find out how to use the grep and awk command together ( preferably in one or 2 shell commands ).. Also and this may be a little more challenging, is if the 3rd slot is empty /blank, then the actual post command that I'd need to do, should be ignored completely..

is it possible to do this?

thanks again

Some modification to the awk command:

Code:

awk '/LUN Path:/{ if ( $3 ~ /.+/ ) print | "echo rm " $3 }' filename

As you can see there is no need of grep, since awk can manage regular expressions as well. This code matches only the lines containing the "Lun Path:" string. The if statement inside the brackets takes care of non-empty fields (the command is executed if $3 matches any string of 1 or more characters). If you want to match more strictly the file name to remove, you have to refine the regular expression in the if statement.

And while awk is blazing fast, and little, the shell is
already running ... building up on grails example:

Code:

while read _ _ line; do if [[ "$line" =~ server ]]; then echo rm "$line"; fi; done < file

The bash version executes in 0m0.001s, the awk one in 0m0.023s on my machine. ;}

Cheers,
Tink

If just concerned about line having something you could also go with:

Code:

while read _ _ line; do [[ "$line" ]] && echo rm "$line"; done < file

thanks for the answers

thanks for everyones time and input. You've been great help !
pb solved.