Suppose I have a file.txt with the following lines :

hello myname1 is yellow.pcapng red
festive myname33 is hddd.pcapng dfdf
crude myname44 is hello.pcapng

Now my goal is to filter to the lines so it outputs to out.txt as follows :

myname1 yellow.pcapng
myname33 hddd.pcapng
myname44 hello.pcapng

Now I know that I can use :

grep -oh "\w*myname\w*" /tmp/file.txt  > /tmp/out.txt
grep -o '[^ ]\+g' /tmp/file.txt > /tmp/out.txt 

to get the both respective parts of the expression individually. How do I combine these commands so that I get my desired output?

  • 3
    do you have to use grep? You have a problem that's begging for an awk solution, and awk should be available everywhere that grep is.
    – Jeff Schaller
    Jun 3 '19 at 18:05
  • I was only familiar with grep and not awk, could you show me how to do using awk possibly? Jun 3 '19 at 18:13
  • @JeffSchaller It's actually begging for a cut solution, since this is exactly what cut is supposed to do
    – ChatterOne
    Jun 4 '19 at 9:57
  • Good thing there is a cut solution, @ChatterOne!
    – Jeff Schaller
    Jun 4 '19 at 10:30

Given your sample data, you could assume that words #2 and #4 are what you want to extract; you'd express that in awk with:

awk '{ print $2, $4 }' < /tmp/file.txt > /tmp/out.txt

You could use cut:

cut -d' ' -f2,4 < /tmp/file.txt > /tmp/out.txt 

Using awk instead of grep.

awk '{print $2,$4}' /tmp/file.txt > /tmp/out.txt

You are piping the output of cat file.txt to awk.

Then using awk expressions '{print $2,$4}', you are printing the 2nd and 4th field of the split line, with a space to separate.

Your output will be how you desire.


Could do this too:

cat file.txt | sed "s/.*\(myname[0-9]*\) is \([^ ]*\).*/\1 \2/g" | grep ^myname > /tmp/out.txt


Since shell script method has been provided above, Tried in Python and worked fine too

for z in k:
    o.append(z.strip().split(' ')[1])
        o.append(z.strip().split(' ')[3])
for d in range(0,len(o),2):
    print " ".join(o[d:d+2])


myname1 yellow.pcapng
myname33 hddd.pcapng
myname44 hello.pcapng

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