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paste command

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The Unix paste command combines files horizontally into a single line.. For simple cases it is Ok. for complex cases you need to use Perl or AWK instead.

When two files are supplied as arguments,  paste writes to standard output the first line of the first file, a Tab character, and the first line from the second file, and then continues with the second line until all the lines have been written out. If one file is shorter than the other, blank lines are used for the missing lines.

If you have two files, it would display the first file in the left column and the second file in the second column. The paste command has three main  functions:


Following is the general format of the paste command.

       paste [ -d[list] ]  [-]file_list
       paste -s [ -d[list ]  file_list


The following list describes the options and their arguments that may be used to control how paste functions.

- The standard input. Causes paste to read one file from the standard input.
-dlist Delimiter. Allows you to define what character you want to use to separate columns of output. If you do not specify a list, the output columns are displayed immediately next to each other.
If -d is not specified, a tab character separates all columns.
The list is zero or more characters used for output delimiters, replacing the default tab character. The list must follow immediately after the -d option. If list consists of multiple characters, paste uses the first character to separate columns one and two, the second character between columns two and three, and so on. If the list is completely used and more columns exist, then the list is reused from the beginning. Thus it is a circular delimiter list.
The list may contain any of the following standard C escape sequences:
\n A newline
\t A tab
\\ A backslash; since a backslash is a special character you must escape it.
\0 No character at all. Same as -d without a list. But may be used in multi- character list. Does not actually place a character on the output.
You may have to quote the list to keep the shell from interpreting certain characters. For example, to pass a backslash to paste you would have to type -d"\\" or -d'\'.
-s Serial output. Allows you to combine all lines of each file into one line of output. The -d option may be used to change the output delimiter. The last character of output is always a new-line.


The following describes the argument that may be passed to the paste command.

file_list One or more files read and displayed in the appropriate format.


The following messages may be displayed if paste encounters a problem.

line too long An input line is too long. The longest possible input is 511 characters.
too many files Only 12 input files can be specified; you entered 13 or more. The -s option is restricted by this limit.


The --delimiters (-d) switch is a list of one or more delimiters to use in place of a Tab. The paste command cycles through the list if it needs more delimiters than are provided in the list, as shown below:


shopt -s -o nounset

declare -r ROBOTS="robots.txt"
declare -r COLUMN1="column1.txt"
declare -r COLUMN2="column2.txt"
declare -i LINES

LINES='wc -l < "$ROBOTS"'

head -$LINES < "$ROBOTS" > "$COLUMN1" 

tail +$LINES < "$ROBOTS" > "$COLUMN2"

paste --delimiters="|" "$COLUMN1" "$COLUMN2"

rm "$COLUMN1"
rm "$COLUMN2"
exit 0

Suppose you had a file called order1.txt containing an item separated into a list of the fields on single lines.

Birchwood China Hutch

The paste --serial (-s) switch pastes all the lines of each file into a single item, as opposed to combining a single line from each file one line at a time. This switch recombines the separate fields into a single line.

$ paste --serial --delimiters="," order1.txt
Birchwood China Hutch,475.99,1,756

To merge the lines of two or more files so that the lines follow one another, use the sort command with the -m switch.


  1. Type paste first city and press Return. The two files are combined line-by-line with tabs separating the two. Your screen should look like the following display.
           cj> paste first city
           Name    City
           Someone Austin
           Anyone  Dallas
  2. Type paste -s -d: first city and press Return. This creates a single line of output. Your screen should resemble the following display:
           cj> paste -d: -s first second
  3. Type ls /bin | paste - - - - and press Return to list out the files in the /bin directory in 4-column output. Each - tells paste to read a line from standard input. Since there are four files to read from, four columns are created for output.
           cj> ls /bin | paste - - - -
           adb     ar   as   basename

Top Visited
Past week
Past month


Old News ;-)


The paste command can be used to paste lines from one or more files (one of them can be a standard input) to the standard output, which can be redirected to a file. The paste command concatenates the line from each input file to the output file separating them by the tab character (default).

Following is a list of flags that can be used with the paste command:

Examples Let us assume that we have two files, file1 and file2, whose contents are shown below:

more file1
computer1 16MB 1.2GB 17inch CDROM
computer2 8MB 840MB 14inch
computer3 12MB 1.6GB 17inch
computer4 4MB 270MB 14inch

more file2
computer1 1stfloor office5
computer3 2ndfloor office9A
computer4 1stfloor office2
computer5 3rdfloor office1

If you want to merge file1 and file2, use the following command:

paste file1 file2
computer1 16MB 1.2GB 17inch CDROM       computer1 1stfloor office5
computer2 8MB 840MB 14inch      computer3 2ndfloor office9A
computer3 12MB 1.6GB 17inch     computer4 1stfloor office2
computer4 4MB 270MB 14inch      computer5 3rdfloor office1

The lines from file1 and file2 are separated by tab characters.

If you want to modify the default separator from the tab character to, say, / (slash), use the -d flag in the following command:

paste -d"/" file1 file2
computer1 16MB 1.2GB 17inch CDROM/computer1 1stfloor office5
computer2 8MB 840MB 14inch/computer3 2ndfloor office9A
computer3 12MB 1.6GB 17inch/computer4 1stfloor office2
computer4 4MB 270MB 14inch /computer5 3rdfloor office1

If you want to merge the lines from within each input file, use the -s flag in the following command:


The Last but not Least Technology is dominated by two types of people: those who understand what they do not manage and those who manage what they do not understand ~Archibald Putt. Ph.D

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Last modified: March 12, 2019