Paste command is one of the useful commands in Unix or Linux operating system. It is used to join files horizontally (parallel merging) by outputting lines consisting of lines from each file specified, separated by tab as delimiter, to the standard output. When no file is specified, or put dash (“-“) instead of file name, paste reads from standard input and gives output as it is until a interrupt command [Ctrl-c] is given. Syntax:
paste [OPTION]... [FILES]...
Let us consider three files having name state, capital and number. state and capital file contains 5 names of the Indian states and capitals respectively. number file contains 5 numbers.
$ cat state
$ cat capital
Without any option paste merges the files in parallel. The paste command writes corresponding lines from the files with tab as a deliminator on the terminal.
$ paste number state capital
1 Arunachal Pradesh Itanagar
2 Assam Dispur
3 Andhra Pradesh Hyderabad
4 Bihar Patna
5 Chhattisgrah Raipur
In the above command three files are merges by paste command. Options: 1. -d (delimiter): Paste command uses the tab delimiter by default for merging the files. The delimiter can be changed to any other character by using the -d option. If more than one character is specified as delimiter then paste uses it in a circular fashion for each file line separation.
Only one character is specified
$ paste -d "|" number state capital
More than one character is specified
$ paste -d "|," number state capital
First and second file is separated by '|' and second and third is separated by ','.
After that list is exhausted and reused.
2. -s (serial): We can merge the files in sequentially manner using the -s option. It reads all the lines from a single file and merges all these lines into a single line with each line separated by tab. And these single lines are separated by newline.
$ paste -s number state capital
1 2 3 4 5
Arunachal Pradesh Assam Andhra Pradesh Bihar Chhattisgrah
Itanagar Dispur Hyderabad Patna Raipur
In the above command, first it reads data from number file and merge them into single line with each line separated by tab. After that newline character is introduced and reading from next file i.e. state starts and process repeats again till all files are read. Combination of -d and -s: The following example shows how to specify a delimiter for sequential merging of files:
$ paste -s -d ":" number state capital
Arunachal Pradesh:Assam:Andhra Pradesh:Bihar:Chhattisgrah
3. –version: This option is used to display the version of paste which is currently running on your system.
$ paste --version
paste (GNU coreutils) 8.26
Packaged by Cygwin (8.26-2)
Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later .
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Written by David M. Ihnat and David MacKenzie.
Applications of Paste Command
1. Combining N consecutive lines: The paste command can also be used to merge N consecutive lines from a file into a single line. Here N can be specified by specifying number hyphens(-) after paste.
With 2 hyphens
$ cat capital | paste - -
With 3 hyphens
$ paste - - - < capital
Itanagar Dispur Hyderabad
2. Combination with other commands: Even though paste require at least two files for concatenating lines, but data from one file can be given from shell. Like in our example below, cut command is used with -f option for cutting out first field of state file and output is pipelined with paste command having one file name and instead of second file name hyphen is specified. Note: If hyphen is not specified then input from shell is not pasted.
$ cut -d " " -f 1 state | paste number
$ cut -d " " -f 1 state | paste number -
Ordering of pasting can be changed by altering the location of hyphen:
$ cut -d " " -f 1 state | paste - number
?list=PLqM7alHXFySFc4KtwEZTANgmyJm3NqS_L This article is contributed by Akash Gupta. If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to email@example.com. See your article appearing on the GeeksforGeeks main page and help other Geeks. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.