JOIN(1)

💖 NAME 💖

Hii bestie, welcome to JOIN(1) — the manual page for join, the icon that, for each pair of input lines with identical join fields, writes a line to standard output. The default join field is the first one, delimited by blanks. ✨

Also: when FILE1 or FILE2 (not both) is -, it reads standard input. Slay.

🦋 SYNOPSIS 🦋

join [OPTION]... FILE1 FILE2

🌸 DESCRIPTION 🌸

Okay so picture this: join takes two files, looks for lines with matching join fields, and for each pair of input lines with identical join fields, writes a line to standard output. The default join field is the first, delimited by blanks. That's the whole main-character move. 💅

And when FILE1 or FILE2 (not both) is -, it reads standard input. Not both, bestie — one of them. 🫶

✨ OPTIONS ✨

• -a <FILENUM> — also print unpairable lines from file FILENUM, where FILENUM is 1 or 2, corresponding to FILE1 or FILE2.
  • Possible values:
    • 1
    • 2
• -v <FILENUM> — like -a FILENUM, but suppress joined output lines.
  • Possible values:
    • 1
    • 2
• -e <EMPTY> — replace missing input fields with EMPTY.
• -i, --ignore-case — ignore differences in case when comparing fields.
• -j <FIELD> — equivalent to '-1 FIELD -2 FIELD'.
• -o <FORMAT> — obey FORMAT while constructing the output line.
• -t <CHAR> — use CHAR as the input and output field separator.
• -1 <FIELD> — join on this FIELD of file 1.
• -2 <FIELD> — join on this FIELD of file 2.
• --check-order — check that the input is correctly sorted, even if all input lines are pairable.
• --nocheck-order — do not check that the input is correctly sorted.
• --header — treat the first line in each file as field headers, print them without trying to pair them.
• -z, --zero-terminated — line delimiter is NUL, not newline.
• -h, --help — print help.
• -V, --version — print version.

🌈 VERSION 🌈

v(uutils coreutils) 0.12.0

Mwah 💋 and that's the page! This little icon is from v(uutils coreutils) 0.12.0, dated 2026-09-17, and JOIN(1) is signing off. Periodt. 👑