Join lines of two sorted files by matching on a common field. If either file1 or file2 is -, read from standard input. Often used to merge data stored in text-based file formats such as comma-separated-value formatted spreadsheets.
Linux Commad Options: -1 fieldnum1
The join field in file1 is fieldnum1. Default is the first field. -2 fieldnum2
The join field in file2 is fieldnum2. Default is the first field. -a filenum
Print a line for each unpairable line in file filenum, in addition to the normal output. --check-order, --nocheck-order
Check or do not check that the files are correctly sorted on the join fields. -e string
Replace missing input fields with string. -i, --ignore-case
Ignore case differences when comparing fields. -o fieldlist
Order the output fields according to fieldlist, where each entry in the list is in the form filenum.fieldnum. Entries are separated
by commas or blanks. -t char
Specifies the field-separator character (default is whitespace). -v filenum
Print only unpairable lines from file filenum. --help
Print help message and then exit. --version
Print the version number and then exit.
Examples:
join -t'\0' -a1 -a2 file1 file2 Union of sorted files
join -t'\0' file1 file2 Intersection of sorted files
join -t'\0' -v2 file1 file2 Difference of sorted files
join -t'\0' -v1 -v2 file1 file2 Symmetric Difference of sorted files
