Bash：如何使用 sed 仅替换文件中的最后一次出现？
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Bash: how to use sed to replace only the last occurence in a file?
提问by Luca Borrione
Having a file containing repeated commented lines like:
有一个包含重复注释行的文件，例如：
# ScriptAlias /cgi-bin/ "somepath"
# ScriptAlias /cgi-bin/ "otherpath"
I want to add a line only after the last occurence resulting in
我只想在最后一次出现后添加一行，导致
# ScriptAlias /cgi-bin/ "somepath"
# ScriptAlias /cgi-bin/ "otherpath"
ScriptAlias /cgi-bin/ "mypath"
To do so I'm using this command:
为此，我正在使用此命令：
sed -i 's:^\(.*ScriptAlias /cgi-bin/.*\): \nScriptAlias /cgi-bin/ "mypath":' file
But this results in adding my line after each occurence like:
但这会导致在每次出现后添加我的行，例如：
# ScriptAlias /cgi-bin/ "somepath"
ScriptAlias /cgi-bin/ "mypath"
# ScriptAlias /cgi-bin/ "otherpath"
ScriptAlias /cgi-bin/ "mypath"
How can I tell sed to replace only the last occurence?
EDITED:
If there's no way to solve it using sed (as said in comments), please provide alternatives reaching the same result, thanks.
我怎么能告诉 sed 只替换最后一次出现？
编辑：
如果无法使用 sed 解决它（如评论中所述），请提供达到相同结果的替代方法，谢谢。
EDITED:
The repeated lines can be separeted and with other lines between them like
编辑：
重复的行可以分开，并在它们之间使用其他行，如
# ScriptAlias /cgi-bin/ "somepath"
# ScriptAlias /cgi-bin/ "otherpath"
# ScriptAlias /cgi-bin/ "another-path"
ScriptAlias /foo/ "just-jump"
# ScriptAlias /cgi-bin/ "that's the last"
回答by glenn Hymanman
回答by Kent
alternative with awk:
用 awk 替代：
awk '/ScriptAlias \/cgi-bin\//{x=NR} {a[NR]=kent$ echo "# ScriptAlias /cgi-bin/ "somepath"
fooo
# ScriptAlias /cgi-bin/ "otherpath"
bar
"|awk '/ScriptAlias \/cgi-bin\//{x=NR} {a[NR]=# ScriptAlias /cgi-bin/ somepath
fooo
# ScriptAlias /cgi-bin/ otherpath
$$$here comes new line$$$
bar
;}END{for(i=1;i<=NR;i++){if(i==x+1)print "$$$here comes new line$$$"; print a[i];}}'
;}END{for(i=1;i<=NR;i++){if(i==x+1)print "$$$here comes new line$$$"; print a[i];}}' file
test:
测试：
tail -r temp | awk '{line="yourline"}{if(krithika.337> cat temp
# ScriptAlias /cgi-bin/ "somepath"
# ScriptAlias /cgi-bin/ "otherpath"
# ndmxriptAlias /cgi-bin/ "otherpath"
# ScriptAlias /cgi-bin/ "otherpath"
# bdjiptAlias /cgi-bin/ "otherpath"
krithika.338> tail -r temp | awk '{line="yourline"}{if(ex input_file << "DONE"
/ScriptAlias \/cgi-bin\/ "otherpath"
a
ScriptAlias /cgi-bin/ "mypath"
.
:1
/ScriptAlias \/cgi-bin\/ "another-path"
a
ScriptAlias /cgi-bin/ "just-jump"
.
:x
DONE
~/ScriptAlias/&&last==0){print line"\n"ex input_file << "DONE"
$
?ScriptAlias \/cgi-bin\/ "otherpath"
a
ScriptAlias /cgi-bin/ "mypath"
.
$
?ScriptAlias \/cgi-bin\/ "another-path"
a
ScriptAlias /cgi-bin/ "just-jump"
.
:x
DONE
;last=1}else print}' | tail -r
# ScriptAlias /cgi-bin/ "somepath"
# ScriptAlias /cgi-bin/ "otherpath"
# ndmxriptAlias /cgi-bin/ "otherpath"
# ScriptAlias /cgi-bin/ "otherpath"
yourline
# bdjiptAlias /cgi-bin/ "otherpath"
krithika.339>
~/ScriptAlias/&&last==0){print line"\n"##代码##;last=1}else print}' | tail -r
output:
输出：
##代码##回答by Vijay
tested below:
测试如下：
##代码##回答by pizza
It is a task for the editor.
这是编辑的任务。
##代码##In last occurence mode.
在最后出现模式下。
##代码##