Reading lines in a file matching a pattern

Shell Programming and Scripting
1

Hi,

I need to redirect the lines in a file to a different file if the character starting from 2 to 6 in the line are numerical [0-9].

Please let me know if anyone have any script to do this.

Thanks,
Ranjit

2

Can you give us an example set of the lines of the file.

3

Hi,

First of all, i would like to give you a suggestion that while you are here. try to give a example about your thread. Then it will be easy for others to understand your requirements and give you the suitable solution.

I assume your requirements as follow:

input:

a23456 line is the first line
abcd line is the second line
12345644 line is the third line
sadfjkl line is the forth line

output ( content in another file):

a23456 line is the first line
12345644 line is the third line

code:
awk '{
if (substr($0,2,5)+0==substr($0,2,5))
print
}' firstfile > secondfile

4

using same example

# awk 'substr($0,2,5) ~ /[0-9]+/' "file"
a23456 line is the first line
12345644 line is the third line
5

using Perl:

#!/usr/bin/perl
# extract_num_lines.pl
while (<>) {
    print if (m/^.\d{5}/);
}

Run this script as:

perl extract_num_lines.pl num_file > new_file

^ represents start of line
. represents a single character
\d represents a digit
\d{5} represent exactly five digits