grep command

castor0troy · 04-10-2013, 08:22 AM

the keyword in the main file should 'begin with' the keyword in input.txt
123goldcoast doesnt begin with 'goldcoast'

millgates · 04-10-2013, 10:21 AM

With regexp, you can match the begining of the line with ^. So, for example in awk, it could look like this:

Code:

keyword="^goldcoast";
if ($0 ~ keyword) { ... }

or with grep:

Code:

grep "^goldcoast" file

grail · 04-10-2013, 11:52 AM

As the keyword is to be at the start of the line, is there any definitive delimiter at the end of the word that would allow us to set the first field equal to all words potentially in the input file?

castor0troy · 04-10-2013, 09:29 PM

thanks for the support.
i am trying to learn how to execute an awk script.
how do i do this?

should i save it as file.sh on the server?

chrism01 · 04-10-2013, 10:19 PM

Save it as file.awk and make it executable (chmod u+x file.awk)

castor0troy · 04-10-2013, 11:06 PM

thanks
i saved this as ss.awk and executed the script echo | awk -f ss.awk but got this error.
can someone check if there is an error in the awk file.

awk: ss.awk:1: awk '
awk: ss.awk:1: ^ invalid char ''' in expression

==========================

awk '
NR == FNR { kw[$0]=0; }
NR != FNR {
for (w in kw) {
split($0,a,w);
kw[w]+= (length(a)-1);
}
}
END {
for(w in kw) {print w, kw[w];}
}
' input.txt file.txt >output.txt

millgates · 04-11-2013, 12:21 AM

In this form, it's actually a shell script which calls awk. To make it an awk script, it should look like this:

Code:

#!/usr/bin/awk -f

NR == FNR { kw[$0]=0; }
NR != FNR {
    for (w in kw) {
        split($0,a,w);
        kw[w]+= (length(a)-1);
    }
}
END {
    for(w in kw) {print w, kw[w];}
}

castor0troy · 04-11-2013, 12:28 AM

thanks.
you have removed this line.
' input.txt file.txt >output.txt

how do i define the files?

pan64 · 04-11-2013, 01:14 AM

you just execute the script:
<scriptname> input.txt file.txt > output.txt

w1k0 · 04-11-2013, 05:34 PM

1. Prepare cat file:

Code:

cat1
1cat
cat2
2cat
cat3
3cat
cat4
4cat
cat5
5cat

2. Prepare cat.sh script:

Code:

#!/bin/bash
mkdir cat\?
cat="grep -c '^cat'"
eval "$cat cat" > cat\?/cat.cat

3. You will find the result in cat\?/cat.cat file.

(The answer is 5.)

castor0troy · 04-12-2013, 03:19 AM

ok guys.
after 2 hrs of struggling i managed to run the script successfully.
echo | awk -f ss.awk input.txt file.txt >output.txt

it worked for smaller files.
however its not giving results for bigger files.
input.txt is 20mb and file.txt is 2gb.

is there anything besides awk that i could use for bigger files?

pan64 · 04-12-2013, 03:39 AM

that echo | at the beginning should be removed.
awk should be able to handle that file also.
Have you got any (error) message?

grail · 04-12-2013, 05:05 AM

Agreed, very hard to diagnose:

Quote:

however its not giving results for bigger files.

castor0troy · 04-12-2013, 06:22 AM

Quote:

Originally Posted by pan64

that echo | at the beginning should be removed.
awk should be able to handle that file also.
Have you got any (error) message?

no error message.script just keeps on running but no results.

i tried the grep command on the same files and got this error
]# grep -of input.txt file.txt |sort|uniq -c >output.txt
grep: file.txt: Input/output error

any idea?

pan64 · 04-12-2013, 07:05 AM

probably in /var/log you will see some interesting messages...