paste Command in Linux: Merge Lines, Delimiters & Practical Examples

Combine two parallel lists into columns — for example names in one file and scores in another.

Create sample files and merge them:

printf 'A1\nA2\nA3\n' > /tmp/f1.txt
printf 'B1\nB2\n' > /tmp/f2.txt
paste /tmp/f1.txt /tmp/f2.txt

Sample output:

A1	B1
A2	B2
A3

The third row has only A3 because f2.txt ran out of lines — paste does not pad missing fields.

Use -s when you need one line of tab- or comma-separated values from a multi-line file.

Run the command:

printf 'A1\nA2\nA3\n' > /tmp/f1.txt
paste -s /tmp/f1.txt

Sample output:

A1	A2	A3

Add -d ',' when downstream tools expect CSV-style commas instead of tabs.

When files differ in length, paste keeps going with whatever lines remain in the longer file.

Run the command:

paste /tmp/f1.txt /tmp/f2.txt
wc -l /tmp/f1.txt /tmp/f2.txt

Sample output:

A1	B1
A2	B2
A3	
  3 /tmp/f1.txt
  2 /tmp/f2.txt
  5 total

Use wc -l first when strict pairing matters — trim or pad files before merging if every row must have the same number of columns.

Replace tabs with commas when feeding spreadsheets or tools that expect CSV.

Run the command:

paste -d ',' /tmp/f1.txt /tmp/f2.txt

Sample output:

A1,B1
A2,B2
A3,

The trailing comma on A3, marks an empty second column where f2.txt had no third line.

Merge every two consecutive lines without creating intermediate files — useful for key/value pairs stored on alternating lines.

Run the command:

paste - - < /tmp/f1.txt

Sample output:

A1	A2
A3

Each - is one copy of stdin; paste reads two lines per output row. Use three - arguments to group triples.

A typical reporting pattern: headers plus data rows from parallel extracts.

Run the command:

printf 'name\nalice\nbob\n' > /tmp/names.txt
printf '90\n85\n' > /tmp/marks.txt
paste -d ',' /tmp/names.txt /tmp/marks.txt

Sample output:

name,90
alice,85
bob,

Redirect to a .csv file when the output is final: paste -d ',' names.txt marks.txt > report.csv.

Multiple characters in -d are reused in order — handy when columns need different separators.

Run the command:

paste -d ',;' /tmp/f1.txt /tmp/f2.txt

Sample output:

A1,B1
A2;B2
A3,

With two files, the first delimiter separates columns on row 1, the second on row 2, then the pattern repeats. The lone A3, shows the third row still uses , but f2.txt had no third line.

Process substitution feeds two command streams into paste in one pipeline.

Run the command:

paste <(cut -d ':' -f 1 /etc/passwd | head -3) <(cut -d ':' -f 3 /etc/passwd | head -3)

Sample output:

root	0
daemon	1
bin	2

First column is usernames; second is UID fields from the same lines of /etc/passwd. See the cut command for field selection details.