Shell分组文件重复模式

Question

假设我有一个文件

a,anything,keyboard
b,anything,mouse
c,anything,door
a,anything,monitor
d,anything,keyboard

结果我想要

a,anything,keyboard - monitor
b,anything,mouse
c,anything,door
d,anything,keyboard

模式“a”重复，我想在结果中合并“键盘”和“监视器”。

我的问题是如何将在每行开头重复的模式（在本例中为“a”）合并为一行添加什么是不同的（在此示例中，添加单词“monitor”

cat file.csv | cut -d'，' - f1 |排序-u 结果：

a
b
c
d

我想要结果：

a,anything,keyboard - monitor
b,anything,mouse
c,anything,door
d,anything,keyboard

Answer 1

我称之为分组而非排序。

gawk （GNU awk）解决方案：

awk -F, 'BEGIN{ PROCINFO["sorted_in"]="@val_str_asc" }{ a[$1]=($1 in a)? a[$1]" - "$3 : $0 }
         END{ asort(a); for(i in a) print a[i] }' file

输出：

a,anything,keyboard - monitor
b,anything,mouse
c,anything,door
d,anything,keyboard