Find duplicate column and separate them to a file or variable(Bash)

Question

I have output like ; (The columns separated by tab \t)

name1   something1
name1   something2
name1   something3
name2   something4
name2   something5

For this output I need two output (if there is name3, I will need 3 output) like

name1   something1
name1   something2
name1   something3

and

name2   something4
name2   something5

I think this will be done by AWK but I couldn't create magic words.

What is the best way to do this?

I need a condition to read $1 "1.column" and print all of them(not delete duplicates) unless it will change and print other columns ($2,$3,...)

I think using loop it prints first output and so on.

Answer 1

Try this:

awk -F'\t' '{print>$1;}' file

When the above command is complete, there will be two more files in the directory:

$ cat name1
name1   something1
name1   something2
name1   something3
$ cat name2
name2   something4
name2   something5

How it works

• -F'\t'

  This tells awk to use a tab as the field separator.

• print>$1

  This tells awk to print each line to the a file named after the first field.

Removing illegal characters from file names

Suppose the input file looks like:

$ cat file
name/1  something1
name/1  something2
name/1  something3
name/2  something4
name/2  something5

The following code creates files based on the name field but with the / removed:

awk -F'\t' '{name=$1; gsub(/[/]/, "", name); print>name;}' file

The above was tested on GNU awk and ran successfully. If your awk does not accept , then try:

awk -F'\t' '{name=$1; gsub("/", "", name); print>name;}' file

or:

awk -F'\t' '{name=$1; gsub(/\//, "", name); print>name;}' file

Answer 2

I think this should work:

mkdir tmp; cd tmp
while IFS= read line; do
    echo "$line" >> $(echo "$line" | awk '{print $1}')
done
cat *

This reads input line by line and appends each line accordingly to it's first argument.

If you want to stream it to variable:

while IFS= read line; do
    key="$(echo "$line" | awk '{print $1}')"
    eval "INPUT_$key='\$INPUT_$key\$line'"
done

If you have big demands from it, use:

#!/usr/bin/python

import sys
import re

for line in sys.stdin:
    f = open(re.split("\s+", line, 1), 'a')
    f.write(line)
    f.close()

This will work. Must. It can't fail.