服务器评测
一.附加文本
使用a\在指定行后面附加1行或多行；若不指定放置的位置，则默认放到每一行的后面。
附加文本时，不允许指定范围，只允许一个地址模式。
附加格式：
[address] a\
text\
text\
…
text
注意：
1.a\通知sed对a\后面的内容进行附加操作。
2.每行后面都有”\”，当sed执行到\时，将创建一个新行，并将内容添加进去。
3.最后一行不能有”\”。
例子：
如果将附加的第一行最后的”\”去掉，那么运行脚本将会报错。
pg append.sed
#!bin/sed -f
# append text
/company/ a\
Then suddenly it happened.
_yeeXun.
执行之后：
sed -f append.sed quote.txt
sed: Unrecognized command: _yeeXun.
修改之后
pg append.sed
#!bin/sed -f
# append text
/company/ a\
Then suddenly it happened.\
_yeeXun.
执行脚本：
sed -f append.sed quote.txt
The honeysuckle band played all night long for noly $90.
It was an evening of splendid music and company.
Then suddenly it happened.
_yeeXun.
Too bad the disco floor fell through at 23:10.
The local nurse Miss P.Neave was in attendance.
因为sed不与原文件打交道，编辑的只是其一个拷贝，所以我们附加的数据不会写到文件中；
当执行上面的命令之后，我们查看下quote.txt文件：
pg quote.txt
The honeysuckle band played all night long for noly $90.
It was an evening of splendid music and company.
Too bad the disco floor fell through at 23:10.
The local nurse Miss P.Neave was in attendance.
二.修改文本
使用c\修改指定行，格式：
[address[,address]] c\
text\
text\
…
text
address：行位置，可以使用正则表达式定位，也可以直接指定行号。
text：为替换的文本，注意最后一行没有”\”。
例子
替换第三行数据：
pg change.sed
# change date
/bad/ c\
[Two good.]\
next goods.
运行脚本：
sed -f change.sed quote.txt
The honeysuckle band played all night long for noly $90.
It was an evening of splendid music and company.
[Two good.]
next goods.
The local nurse Miss P.Neave was in attendance. 三.添加文本
在指定行前面添加数据。
[address] i\
text\
text\
…
text
address：行位置，可以使用正则表达式定位，也可以直接指定行号。
text：为替换的文本，注意最后一行没有”\”。
例如：
pg insert.sed
# insert data
/.*ing/ i\
[the insert date].
运行脚本：
sed -f insert.sed quote.txt
The honeysuckle band played all night long for noly $90.
[the insert date].
It was an evening of splendid music and company.
Too bad the disco floor fell through at 23:10.
The local nurse Miss P.Neave was in attendance.
四.删除文本
删除文件中的内容，删除1行或者连续的多行，或者匹配某个模式的所有行格式：
[address[,address]] d
文件信息：
pg quote.txt
The honeysuckle band played all night long for noly $90.
It was an evening of splendid music and company.
Too bad the disco floor fell through at 23:10.
The local nurse Miss P.Neave was in attendance.
删除第一行：
sed ‘1d’ quote.txt
It was an evening of splendid music and company.
Too bad the disco floor fell through at 23:10.
The local nurse Miss P.Neave was in attendance.
删除第一到第三行：
sed ‘1,3d’ quote.txt
The local nurse Miss P.Neave was in attendance.
删除最后一行：
sed ‘$d’ quote.txt
The honeysuckle band played all night long for noly $90.
It was an evening of splendid music and company.
Too bad the disco floor fell through at 23:10.
使用正则表达式删除符合条件的所有行。
删除包含以字母a开头，以字母d结尾，总长为3的行，符合的有第一行（band），第二行（and）。
sed ‘/a.d/d’ quote.txt
Too bad the disco floor fell through at 23:10.
The local nurse Miss P.Neave was in attendance.
五.替换文本，格式：
[address[,address]] s/pattern-to-find/replacement-pattern/[g p w n]
address：可选项
g：默认情况下，只替换首次出现模式，使用g替换全部所有出现的模式；
p：默认sed将所有被替换行写入标准输出，加p将使-n选项无效；-n不打印输出结果。
w：文件名，使用此选项将输出定向到一个文件。
将小写的floor替换为大写的FLOOR：
sed ‘s/floor/FLOOR/’ quote.txt
The honeysuckle band played all night long for noly $90.
It was an evening of splendid music and company.
Too bad the disco FLOOR fell through at 23:10.
The local nurse Miss P.Neave was in attendance.
将包含”$”符号的行$符号删除掉：
包含$符号的行：
sed -n ‘/$.*/p’ quote.txt
The honeysuckle band played all night long for noly $90.
删除$(使用空替代)符号后的行：
sed -n ‘s/\$//p’ quote.txt
The honeysuckle band played all night long for noly 90.
将首次出现的”The”单词替换为”THE”，并输出到另一个文件中
若sed.out存在则向里面写数据，所不存在则创建此文件并写数据：
sed ‘s/The/THE/w sed.out’ quote.txt
THE honeysuckle band played all night long for noly $90.
It was an evening of splendid music and company.
Too bad the disco floor fell through at 23:10.
THE local nurse Miss P.Neave was in attendance.
查看文件sed.out：
pg sed.out
THE honeysuckle band played all night long for noly $90.
THE local nurse Miss P.Neave was in attendance.
