我有一个~23000行的SQL转储，其中包含几个数据库的数据价值。我需要提取这个文件的某个部分(即单个数据库的数据)，并将其放在一个新文件中。我知道我想要的数据的开始行号和结束行号。
谁知道一个Unix命令(或一系列命令)可以从文件中提取16224到16482行之间的所有行，然后将它们重定向到一个新文件中?
当前回答
cat dump.txt | head -16224 | tail -258
应该能行。这种方法的缺点是，您需要做算术来确定tail的参数，并考虑是否希望“between”包含结束行。
其他回答
艾德:使用
ed -s infile <<<'16224,16482p'
-s抑制诊断输出;实际的命令在一个here-string中。具体来说，16224,16482p在所需的行地址范围上运行p (print)命令。
# print section of file based on line numbers
sed -n '16224 ,16482p' # method 1
sed '16224,16482!d' # method 2
由于我们讨论的是从文本文件中提取文本行，所以我将给出一个特殊情况，即您希望提取与某个模式匹配的所有行。
myfile content:
=====================
line1 not needed
line2 also discarded
[Data]
first data line
second data line
=====================
sed -n '/Data/,$p' myfile
将打印[Data]行和其余部分。如果想要从第一行到模式的文本，输入:sed -n '1，/Data/p' myfile。此外，如果您知道两个模式(最好在文本中是唯一的)，则可以使用匹配指定范围的开始行和结束行。
sed -n '/BEGIN_MARK/,/END_MARK/p' myfile
我编写了一个小型bash脚本，您可以从命令行运行它，只要您更新PATH以包含它的目录(或者您可以将它放在PATH中已经包含的目录中)。
用法:$ pinch filename起始行结束行
#!/bin/bash
# Display line number ranges of a file to the terminal.
# Usage: $ pinch filename start-line end-line
# By Evan J. Coon
FILENAME=$1
START=$2
END=$3
ERROR="[PINCH ERROR]"
# Check that the number of arguments is 3
if [ $# -lt 3 ]; then
echo "$ERROR Need three arguments: Filename Start-line End-line"
exit 1
fi
# Check that the file exists.
if [ ! -f "$FILENAME" ]; then
echo -e "$ERROR File does not exist. \n\t$FILENAME"
exit 1
fi
# Check that start-line is not greater than end-line
if [ "$START" -gt "$END" ]; then
echo -e "$ERROR Start line is greater than End line."
exit 1
fi
# Check that start-line is positive.
if [ "$START" -lt 0 ]; then
echo -e "$ERROR Start line is less than 0."
exit 1
fi
# Check that end-line is positive.
if [ "$END" -lt 0 ]; then
echo -e "$ERROR End line is less than 0."
exit 1
fi
NUMOFLINES=$(wc -l < "$FILENAME")
# Check that end-line is not greater than the number of lines in the file.
if [ "$END" -gt "$NUMOFLINES" ]; then
echo -e "$ERROR End line is greater than number of lines in file."
exit 1
fi
# The distance from the end of the file to end-line
ENDDIFF=$(( NUMOFLINES - END ))
# For larger files, this will run more quickly. If the distance from the
# end of the file to the end-line is less than the distance from the
# start of the file to the start-line, then start pinching from the
# bottom as opposed to the top.
if [ "$START" -lt "$ENDDIFF" ]; then
< "$FILENAME" head -n $END | tail -n +$START
else
< "$FILENAME" tail -n +$START | head -n $(( END-START+1 ))
fi
# Success
exit 0
我写了一个叫做splitter的Haskell程序，它就是这样做的:阅读我发布的博客文章。
您可以使用该程序如下:
$ cat somefile | splitter 16224-16482
这就是它的全部。您将需要Haskell来安装它。只是:
$ cabal install splitter
这样就做完了。我希望这个程序对您有用。
