Question

以下是我可以更新图书数量的代码。但我似乎无法做到这一点，以便我可以更新我的其他东西，如书名，作者，价格等。下面是代码：

if grep -q "^$bookname:$author:" BookDB.txt
   then 
   read -p "Update Qty to what?" newQty 
   sed -i "s/^\($bookname:$author:[^:]*\):[^:]*:/\1:$newQty:/" BookDB.txt 
   echo "Book's Qty has been updated successfully!" 
   else 
   echo "$0: BookDB.Txt: no '$title' by '$author'" >&2 
   fi

我的数据库是这样的：

Harry Potter - The Half Blood Prince:J.K Rowling:40.30:10:50
The little Red Riding Hood:Dan Lin:40.80:20:10
Harry Potter - The Phoniex:J.K Rowling:50.00:30:20
Harry Potter - The Deathly Hollow:Dan Lin:55.00:33:790
Little Prince:The Prince:15.00:188:9
Lord of The Ring:Johnny Dept:56.80:100:38
Three Little Pig:Andrew Lim:89.10:290:189
All About Ubuntu:Ubuntu Team:76.00:55:133
Catch Me If You Can:Mary Ann:23.60:6:2
Happy Day:Mary Ann:12.99:197:101
haha:gaga:1:10:1

那么我怎么能改变某些领域，比如当我选择书名时，戒指作者约翰尼·德普的主我可以将书名改为国王的主人？

Lord of The King:Johnny Dept:56.80:100:38

Answer 1

与 user1146332 一样，我也建议切换到更强大的语言。这是一个使用perl的示例。它使用模块Getopt::Long来读取参数并在文件中循环以获得匹配的行。

它似乎有效，但是你可以更好地检查错误，例如，在正则表达式中使用它们之前定义book和author变量。

还有一件事，我使用带有冒号的split()来提取字段，我不知道你如何处理名字中带有冒号的书，但在这种情况下，你需要一个额外的模块来解析CSV ，就像Text::CSV一样，或者用更好的split表达来更加努力。

#!/usr/bin/env perl

use strict;
use warnings;
use Getopt::Long;

my ($book, $author, $newbook, $quantity);

my $r = GetOptions(
        q|book=s| => \$book,
        q|author=s| => \$author,
        q|newbook=s| => \$newbook,
        q|quantity=i| => \$quantity,
) or die;

open my $fh, '<', $ARGV[0] or die;

while ( <$fh> ) { 
        chomp;
        my @f = split /:/;
        next if @f < 5;
        if ( $f[0] =~ m/(?i)\Q$book\E/ &&
             $f[1] =~ m/(?i)\Q$author\E/ ) { 
                $f[0] = defined $newbook ? $newbook : $f[0];
                $f[3] = defined $quantity ? $quantity : $f[3];
                printf qq|%s\n|, join q|:|, @f; 
                next;
        }   

        printf qq|%s\n|, $_; 
}

一个例子：

perl script.pl --book="lord of the ring" --author=dep --newbook="Lord of the King" --quantity=99 infile

收率：

Harry Potter - The Half Blood Prince:J.K Rowling:40.30:10:50
The little Red Riding Hood:Dan Lin:40.80:20:10
Harry Potter - The Phoniex:J.K Rowling:50.00:30:20
Harry Potter - The Deathly Hollow:Dan Lin:55.00:33:790
Little Prince:The Prince:15.00:188:9
Lord of the King:Johnny Dept:56.80:99:38
Three Little Pig:Andrew Lim:89.10:290:189
All About Ubuntu:Ubuntu Team:76.00:55:133
Catch Me If You Can:Mary Ann:23.60:6:2
Happy Day:Mary Ann:12.99:197:101
haha:gaga:1:10:1

Answer 2

sed怎么样？

sed 's/\bLord of The Ring\b/Lord of The King/' file

$ cat file
Harry Potter - The Half Blood Prince:J.K Rowling:40.30:10:50
The little Red Riding Hood:Dan Lin:40.80:20:10
Harry Potter - The Phoniex:J.K Rowling:50.00:30:20
Harry Potter - The Deathly Hollow:Dan Lin:55.00:33:790
Little Prince:The Prince:15.00:188:9
Lord of The Ring:Johnny Dept:56.80:100:38
Three Little Pig:Andrew Lim:89.10:290:189
All About Ubuntu:Ubuntu Team:76.00:55:133
Catch Me If You Can:Mary Ann:23.60:6:2
Happy Day:Mary Ann:12.99:197:101
haha:gaga:1:10:1

$ sed 's/\bLord of The Ring\b/Lord of The King/' file
Harry Potter - The Half Blood Prince:J.K Rowling:40.30:10:50
The little Red Riding Hood:Dan Lin:40.80:20:10
Harry Potter - The Phoniex:J.K Rowling:50.00:30:20
Harry Potter - The Deathly Hollow:Dan Lin:55.00:33:790
Little Prince:The Prince:15.00:188:9
Lord of The King:Johnny Dept:56.80:100:38
Three Little Pig:Andrew Lim:89.10:290:189
All About Ubuntu:Ubuntu Team:76.00:55:133
Catch Me If You Can:Mary Ann:23.60:6:2
Happy Day:Mary Ann:12.99:197:101
haha:gaga:1:10:1

将带有重定向>的输出发送到新文件，或使用sed的-i选项进行就地编辑。

重定向

sed 's/\bLord of The Ring\b/Lord of The King/' file>newfile

使用.bak文件

的地方etit

sed -i.bak 's/\bLord of The Ring\b/Lord of The King/' file

更新特定行中文本文件中的特定字段

2 个答案: