用awk / bash包裹一个超大的列（漂亮的打印）

Question

我有这个表结构（假设分隔符是制表符）：

AAA  BBBB  CCC
 01  Item  Description here
 02  Meti  A very very veeeery long description which will easily extend the recommended output width of 80 characters.
 03  Etim  Last description

我想要的是这个：

AAA  BBBB  CCC
 01  Item  Description here
 02  Meti  A very very veeeery
           long description which
           will easily extend the
           recommended output width
           of 80 characters.
 03  Etim  Last description

这意味着我想将$3拆分为具有预定义WIDTH的字符串数组，其中第一个元素“正常”附加到当前行，并且所有后续元素根据前两列的填充获得新的线宽标识（填充也可以修复，如果这更容易）。

或者，$0中的文本可以用GLOBAL_WIDTH（例如80个字符）分成第一个字符串，“rest” - >第一个字符串用printf“正常”打印，其余部分由GLOBAL_WIDTH - (COLPAD1 + COLPAD2)分割并附加宽度新行，如上所示。

在我的awk格式化之后，我尝试使用fmt和fold（这基本上只是将标题放到表格中），但它们当然不反映awk的字段感知。

如何使用bash工具和/或awk实现这一目标？

Answer 1

首先构建一个测试文件（称为file.txt）：

echo "AA  BBBB  CCC
01  Item  Description here
02  Meti  A very very veeeery long description which will easily extend the recommended output width of 80 characters.
03  Etim  Last description" > file.txt

现在的脚本（称为./split-columns.sh）：

#!/bin/bash
FILE=$1

#find position of 3rd column (starting with 'CCC')
padding=`cat $FILE | head -n1 |  grep -aob 'CCC' | grep -oE '[0-9]+'`
paddingstr=`printf "%-${padding}s" ' '`

#set max length
maxcolsize=50
maxlen=$(($padding + $maxcolsize))

cat $FILE | while read line; do 
  #split the line only if it exceeds the desired length
  if [[ ${#line} -gt $maxlen ]] ; then 
    echo "$line" | fmt -s -w$maxcolsize - | head -n1
    echo "$line" | fmt -s -w$maxcolsize - | tail -n+2 | sed "s/^/$paddingstr/"
  else
    echo "$line";
  fi; 
done;

最后以文件作为单个参数运行它

./split-columns.sh file.txt > fixed-width-file.txt

输出将是：

AA  BBBB  CCC
01  Item  Description here
02  Meti  A very very veeeery long description
          which will easily extend the recommended output
          width of 80 characters.
03  Etim  Last description

Answer 2

你可以尝试Perl one-liner

perl -lpe ' s/(.{20,}?)\s/$1\n\t   /g ' file

给定的输入

$ cat thurse.txt
AAA  BBBB  CCC
 01  Item  Description here
 02  Meti  A very very veeeery long description which will easily extend the recommended output width of 80 characters.
 03  Etim  Last description

$ perl -lpe ' s/(.{20,}?)\s/$1\n\t   /g ' thurse.txt
AAA  BBBB  CCC
 01  Item  Description
           here
 02  Meti  A very very
           veeeery long description
           which will easily extend
           the recommended output
           width of 80 characters.
 03  Etim  Last description

$

如果你想尝试30/40/50的长度窗口

$ perl -lpe ' s/(.{30,}?)\s/$1\n\t   /g ' thurse.txt
AAA  BBBB  CCC
 01  Item  Description here
 02  Meti  A very very veeeery
           long description which will easily
           extend the recommended output width
           of 80 characters.
 03  Etim  Last description

$ perl -lpe ' s/(.{40,}?)\s/$1\n\t   /g ' thurse.txt
AAA  BBBB  CCC
 01  Item  Description here
 02  Meti  A very very veeeery long description
           which will easily extend the recommended
           output width of 80 characters.
 03  Etim  Last description

$ perl -lpe ' s/(.{50,}?)\s/$1\n\t   /g ' thurse.txt
AAA  BBBB  CCC
 01  Item  Description here
 02  Meti  A very very veeeery long description which
           will easily extend the recommended output width of
           80 characters.
 03  Etim  Last description

$