用于在固定宽度文件中的特定位置提取具有空白值的行的 unix 命令答案

【问题标题】：unix command to extract lines with blank values in particular position in a fixed width file用于在固定宽度文件中的特定位置提取具有空白值的行的 unix 命令
【发布时间】：2020-05-01 18:19:36
【问题描述】：

我有一个没有分隔符的固定宽度文件。我想从位置 550-552 中提取具有空白值的固定宽度文件中的行

【问题讨论】：

这是否有机会回答您的问题：unix.stackexchange.com/questions/32170/…？
你可以试试Match pattern on a particular position with grep。

标签： unix flat-file

【解决方案1】：

与sed:

sed -nE '/^.{549}[[:blank:]]{3}/p' file

[[:blank:]] 字符是空格或制表符，如果要匹配三个空格，请将其更改为空格字符。

【讨论】：

【解决方案2】：

您可以使用egrep（或等效的grep -E）：

#first let's build a test file, using seq to make 549 dummy characters (X), then 3 characters, then some more dummy characters (Y):
laptop:~/tmp$ (for n in `seq 1 549`; do echo -n X;done ;echo -n '   '; echo YYYYYYYYYYYYY ) > file
laptop:~/tmp$ (for n in `seq 1 549`; do echo -n X;done ;echo -n 'zzz'; echo YYYYYYYYYYYYY ) >> file
laptop:~/tmp$ (for n in `seq 1 549`; do echo -n X;done ;echo -n '   '; echo YYYYYYYYYYYYY ) >> file
laptop:~/tmp$ (for n in `seq 1 549`; do echo -n X;done ;echo -n '123'; echo YYYYYYYYYYYYY ) >> file

#then do the actual search
laptop:~/tmp$ egrep '.{549}   ' file
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX   YYYYYYYYYYYYY
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX   YYYYYYYYYYYYY

【讨论】：