我有一些文件如下所示。如果该列为空，我需要在第五列中添加字符“C”。我更喜欢现场编辑。
1 87 E P 0 0 131 0, 0.0 0, 0.0 0, 0.0 0, 0.0 0.000 360.0 360.0 360.0 150.0 7.2 83.8 79.2
2 88 E V + 0 0 136 1,-0.1 2,-0.5 3,-0.0 0, 0.0 0.993 360.0 80.8 -61.8 -61.8 7.7 80.9 76.8
3 89 E K S S+ 0 0 195 2,-0.0 2,-0.3 0, 0.0 -1,-0.1 -0.222 77.4 108.3 -45.5 95.3 5.5 82.5 74.2
4 90 E R S S- 0 0 153 -2,-0.5 2,-0.5 2,-0.0 0, 0.0 -0.864 72.2-119.8-173.3 140.8 8.2 84.8 72.9
5 191 E R - 0 0 202 -2,-0.3 2,-0.2 1,-0.0 -2,-0.0 -0.772 46.1-115.0 -83.4 130.6 10.4 85.4 70.0
6 92 E L H - 0 0 109 -2,-0.5 2,-0.5 1,-0.1 -1,-0.0 -0.499 24.5-142.8 -70.2 134.3 14.0 85.3 71.3
7 93 E D + 0 0 126 -2,-0.2 -1,-0.1 1,-0.1 0, 0.0 -0.852 36.1 149.0-101.0 126.6 15.9 88.6 71.1
8 94 E L 0 0 140 -2,-0.5 -1,-0.1 0, 0.0 -2,-0.0 0.735 360.0 360.0-125.7 -35.5 19.6 88.3 70.3
9 95 E E 0 0 235 0, 0.0 -2,-0.0 0, 0.0 0, 0.0 0.494 360.0 360.0 -8.6 360.0 21.0 91.3 68.3
期望输出
1 87 E P C 0 0 131 0, 0.0 0, 0.0 0, 0.0 0, 0.0 0.000 360.0 360.0 360.0 150.0 7.2 83.8 79.2
2 88 E V C + 0 0 136 1,-0.1 2,-0.5 3,-0.0 0, 0.0 0.993 360.0 80.8 -61.8 -61.8 7.7 80.9 76.8
3 89 E K S S+ 0 0 195 2,-0.0 2,-0.3 0, 0.0 -1,-0.1 -0.222 77.4 108.3 -45.5 95.3 5.5 82.5 74.2
4 90 E R S S- 0 0 153 -2,-0.5 2,-0.5 2,-0.0 0, 0.0 -0.864 72.2-119.8-173.3 140.8 8.2 84.8 72.9
5 191 E R C - 0 0 202 -2,-0.3 2,-0.2 1,-0.0 -2,-0.0 -0.772 46.1-115.0 -83.4 130.6 10.4 85.4 70.0
6 92 E L H - 0 0 109 -2,-0.5 2,-0.5 1,-0.1 -1,-0.0 -0.499 24.5-142.8 -70.2 134.3 14.0 85.3 71.3
7 93 E D C + 0 0 126 -2,-0.2 -1,-0.1 1,-0.1 0, 0.0 -0.852 36.1 149.0-101.0 126.6 15.9 88.6 71.1
8 94 E L C 0 0 140 -2,-0.5 -1,-0.1 0, 0.0 -2,-0.0 0.735 360.0 360.0-125.7 -35.5 19.6 88.3 70.3
9 95 E E C 0 0 235 0, 0.0 -2,-0.0 0, 0.0 0, 0.0 0.494 360.0 360.0 -8.6 360.0 21.0 91.3 68.3
答案 0 :(得分：2)
从您的示例中可以看出，如何定义“第五列”并不明显。如果您的列是固定宽度，则“第五列”似乎与第十三个字符位置对应。
如果这是正确的，那么在以十二个字符和一个空白开头的任何行上，用相同的十二个字符和一个C替换。
sed -i 's/^\(............\) /\1C/' filename
如果你是在OSX上，您需要-i ''，因为-i选项需要该平台上的必需参数。如果您的sed完全缺少-i，请尝试使用等效的Perl脚本：
perl -pi -e 's/^(.{12}) /$1C/' filename
如果您的数据始终没有固定宽度，则似乎无法推断出要更换的内容，除非您可以更详细地制定数据描述。
答案 1 :(得分：1)
使用perl：
use strict; use warnings;
while (<>) {
my @f = split(/,/);
my @v=split(/(\s+)/,$f[0]);
$v[7] = " C " if @v < 19;
$v[7].= " " if @v < 17;
$f[0] = join("", @v);
print join(",", @f);
}
执行：
perl script.pl input
输出：
1 87 E P C 0 0 131 0, 0.0 0, 0.0 0, 0.0 0, 0.0 0.000 360.0 360.0 360.0 150.0 7.2 83.8 79.2
2 88 E V C + 0 0 136 1,-0.1 2,-0.5 3,-0.0 0, 0.0 0.993 360.0 80.8 -61.8 -61.8 7.7 80.9 76.8
3 89 E K S S+ 0 0 195 2,-0.0 2,-0.3 0, 0.0 -1,-0.1 -0.222 77.4 108.3 -45.5 95.3 5.5 82.5 74.2
4 90 E R S S- 0 0 153 -2,-0.5 2,-0.5 2,-0.0 0, 0.0 -0.864 72.2-119.8-173.3 140.8 8.2 84.8 72.9
5 191 E R C - 0 0 202 -2,-0.3 2,-0.2 1,-0.0 -2,-0.0 -0.772 46.1-115.0 -83.4 130.6 10.4 85.4 70.0
6 92 E L H - 0 0 109 -2,-0.5 2,-0.5 1,-0.1 -1,-0.0 -0.499 24.5-142.8 -70.2 134.3 14.0 85.3 71.3
7 93 E D C + 0 0 126 -2,-0.2 -1,-0.1 1,-0.1 0, 0.0 -0.852 36.1 149.0-101.0 126.6 15.9 88.6 71.1
8 94 E L C 0 0 140 -2,-0.5 -1,-0.1 0, 0.0 -2,-0.0 0.735 360.0 360.0-125.7 -35.5 19.6 88.3 70.3
9 95 E E C 0 0 235 0, 0.0 -2,-0.0 0, 0.0 0, 0.0 0.494 360.0 360.0 -8.6 360.0 21.0 91.3 68.3
答案 2 :(得分：1)
awk '{a=substr($0, 17, 1);a=(a~/[[:alpha:]]/)?a:"C";print substr($0,1, 16) a substr($0,18)}' file