pivot と unpivot

a.sh

#!/bin/bash

function data() {
    printf "%s\n" $(echo {1..10}{a..c}) | while read x; do
        NUM=${x:0: -1}
        CATE=${x: -1}
        printf "%s\t%s\t%s\n" $NUM $CATE value_$NUM$CATE
    done
}

function pivot() {
    datamash crosstab 1,2 collapse 3
}

function unpivot() {
    read header
    sort -k1 -n | while read x; do
        {
            echo "$header"
            echo "$x" | cut -f2-
        } | datamash transpose | while read y; do
            printf "%s\t%s\n" $(echo "$x" | cut -f1) "$y"
        done
    done
}

data
echo -----
data | pivot
echo -----
data | pivot | unpivot

stdout

1	a	value_1a
1	b	value_1b
1	c	value_1c
2	a	value_2a
2	b	value_2b
2	c	value_2c
3	a	value_3a
3	b	value_3b
3	c	value_3c
4	a	value_4a
4	b	value_4b
4	c	value_4c
5	a	value_5a
5	b	value_5b
5	c	value_5c
6	a	value_6a
6	b	value_6b
6	c	value_6c
7	a	value_7a
7	b	value_7b
7	c	value_7c
8	a	value_8a
8	b	value_8b
8	c	value_8c
9	a	value_9a
9	b	value_9b
9	c	value_9c
10	a	value_10a
10	b	value_10b
10	c	value_10c
-----
	a	b	c
1	value_1a	value_1b	value_1c
10	value_10a	value_10b	value_10c
2	value_2a	value_2b	value_2c
3	value_3a	value_3b	value_3c
4	value_4a	value_4b	value_4c
5	value_5a	value_5b	value_5c
6	value_6a	value_6b	value_6c
7	value_7a	value_7b	value_7c
8	value_8a	value_8b	value_8c
9	value_9a	value_9b	value_9c
-----
1	a	value_1a
1	b	value_1b
1	c	value_1c
2	a	value_2a
2	b	value_2b
2	c	value_2c
3	a	value_3a
3	b	value_3b
3	c	value_3c
4	a	value_4a
4	b	value_4b
4	c	value_4c
5	a	value_5a
5	b	value_5b
5	c	value_5c
6	a	value_6a
6	b	value_6b
6	c	value_6c
7	a	value_7a
7	b	value_7b
7	c	value_7c
8	a	value_8a
8	b	value_8b
8	c	value_8c
9	a	value_9a
9	b	value_9b
9	c	value_9c
10	a	value_10a
10	b	value_10b
10	c	value_10c