Question

我有以下输入：

A|Bash|cat
B|bit|dog
C|Bash|apple
D|Bash|email

我想要以下输出：

cat|Bash|A
apple|Bash|C
email|Bash|D

想法是显示所有包含“ Bash”的行，并以相反的顺序显示其字段。

我可以使用awk向前显示这些行：

$ awk '/Bash/' filename.txt

但是我无法以相反的顺序显示它。有什么办法可以使用awk做到这一点？

Answer 1

使用GNU awk：

$ awk '
BEGIN { 
    FS=OFS="|"                            # set the delimiters
    k="Bash"                              # set the keyword
}
$2==k {                                   # if keyword in 2nd field
    a[$1]=$3                              # hash $3 and index with 1st field
}
END {
    PROCINFO["sorted_in"]="@ind_str_asc"  # control the for traverse order
    for(i in a)                           # loop
        print a[i],k,i                    # ... and output
}' file
cat|Bash|A
apple|Bash|C
email|Bash|D

Answer 2

尝试：

awk -F \| '/Bash/{for(i=NF;i>1;i--){printf("%s|",$i);}print $1}' filename.txt

其中：

    -F \| - sets the delimiter
    /Bash/ - searching the text you want. (to be more precise you should do $2==/Bash/)
    for - loop from NF which is number of fields. here NF=3. to one above 1.
    printf = to print token i, and add the delimiter
    print - outside the loop, printing the first token. this is outside the loop to avoid having the delimiter "|" as the last character printed.

Answer 3

awk -F\| '/Bash/{print $3"|"$2"|"$1}' file 
cat|Bash|A
apple|Bash|C
email|Bash|D

以相反的顺序显示每个由字段分隔的行

3 个答案: