join Command: Tutorial & Examples
Join lines of two files on a common field
join command is a utility in Linux that allows you to join the lines of two files based on a common field. It reads two input files and combines them based on the fields specified with the
-2 options, which specify the field in each input file to be used for joining. By default, the join command outputs a line for each pair of input lines that have identical values in the specified fields.
Here is the basic syntax for using join:
join [options] file1 file2
Some common options for
-1 field: Specifies the field in
file1to use for joining.
-2 field: Specifies the field in
file2to use for joining.
-t char: Specifies the field separator character. The default is the tab character.
-a file: Prints all lines from file, regardless of whether they match a line in the other file.
-e string: Specifies a string to be printed in place of empty fields.
-o format: Specifies the output format.
Here is an example of using
join to join the lines of two files based on the first field:
join -t , -1 1 -2 1 file1.csv file2.csv
This command will join the lines of
file2.csv based on the first field (which is separated by a comma).