Erase line of text file one by one


 
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# 1  
Old 07-10-2011
Erase line of text file one by one

Hi,

I have a BASH script where I would like to identify all the lines of a text file that match specific pattern, and then erase them one by one. The ultimate goal will be to identify all the lines matching the pattern, and then for each line identified prompt the user whether or not to erase it.

Any ideas on where to start with this? Thanks a lot.

Mike
# 2  
Old 07-10-2011
Use 'perl -i' to effect the change on the file being perused...but have you written the prompting section of the script yet?
# 3  
Old 07-10-2011
i came up with this

Code:
#!/bin/bash
FILE=input.txt
OUTFILE=output.txt

PATTERN=e

nawk '$0 ~ p {
printf("Delete this line [%s]? ", $0);
getline ans < "-"
if (tolower(ans) != "y")
        print $0 > outfile
next
}
1 { print $0 > outfile }
' p=$PATTERN outfile=$OUTFILE $FILE

# 4  
Old 07-10-2011
Try something like this:
Code:
#!/bin/bash

FILE=input.txt
OUTFILE=output.txt

PATTERN=e

nawk '$0 ~ p {
  printf("Delete this line [%s]? ", $0)
  getline ans < "-"
  if (tolower(ans) == "y") { 
    next
  }
}
1' p=$PATTERN $FILE > $OUTFILE

 
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