Join multiple files
man join
:
NAME
join - join lines of two files on a common field
SYNOPSIS
join [OPTION]... FILE1 FILE2
it only works with two files.
if you need to join three, maybe you can first join the first two, then join the third.
try:
join file1 file2 | join - file3 > output
that should join the three files without creating an intermediate temp file. -
tells the join command to read the first input stream from stdin
One can join multiple files (N>=2) by constructing a pipeline of join
s recursively:
#!/bin/sh
# multijoin - join multiple files
join_rec() {
if [ $# -eq 1 ]; then
join - "$1"
else
f=$1; shift
join - "$f" | join_rec "$@"
fi
}
if [ $# -le 2 ]; then
join "$@"
else
f1=$1; f2=$2; shift 2
join "$f1" "$f2" | join_rec "$@"
fi