Convert single column file into multiple columns

Question

Basically, I want to convert one column file into multiple column file specified by number of rows.

I do not want to reinvent the wheel. I want to make sure if there is a unix command / or standard way of doing this before writing a custom script.

For example, let's say I have the following file:

$cat input.txt
tom
jack
kim
bart
foo
bar

I want to turn this into 3 row file

$ cat input.txt | my_script --every=3 --delimiter=tab
tom bart
jack foo
kim bar

or 2 row file with the different delimter:

$ cat input.txt | my_script --every=2 --delimiter=,
tom,kim,foo
jack,bart,bar

Answer 1

With awk

 awk -v row=2 '{A[(NR-1)%row]=A[(NR-1)%row]$0" ";next}END{for(i in A)print A[i]}' file

output:

tom  bart 
jack foo 
kim  bar 

here specify no of row you want in raw variable. eg: row=3 for three rows.

Try like this for if you want only break column in specific rows

cat file | xargs -n2

Here 2 for each row contain 2 column, You can use what you want.

Answer 2

Using awk

awk '{a[(NR-1)%n]=a[(NR-1)%n]==""?$1:a[(NR-1)%n] OFS $1}END{for (i=0;i<n;i++) print a[i]}' n=3 OFS="\t" file

tom     bart
jack    foo
kim     bar


awk '{a[(NR-1)%n]=a[(NR-1)%n]==""?$1:a[(NR-1)%n] OFS $1}END{for (i=0;i<n;i++) print a[i]}' n=2 OFS="," file

tom,kim,foo
jack,bart,bar

Answer 3

As a start, you can use sed to get the proper data, e.g.

$ sed -n '1~2p' input
tom
kim
foo

$ sed -n '2~2p' input
jack
bart
bar

Then there are many ways to convert a column into a row. To name a few:

tr '\n' ' ' < file

awk -vORS=' ' 1 file

paste -sd" " file

Answer 4

You can use paste command in UNIX for converting the file into multiple columns. By default, tab is the delimiter. To change the delimiter, use -d option

Command: convert one column file into two columns

paste - - < input.txt

output:

tom  bart 
jack foo 
kim  bar

Command: convert one column file into two columns with , as a delimiter

paste - - -d, < input.txt

Output:

tom,bart 
jack,foo 
kim,bar

Answer 5

What about using xargs?

two records per line:

$ xargs -n2 < file
tom jack
kim bart
foo bar

three records per line:

$ xargs -n3 < file
tom jack kim
bart foo bar