Trying to modify file with shell script - with /bin/ex

Question

I have an xml file I need to modify:

...
</web-app>

I want to add some text before this line. I've tried with the simple text and it works fine (I used /bin/ex):

s/<\/web-app/test &/

so I get what I want:

...
test </web-app>

But the real text I need to insert is:

<error-page>
<error-code>400</error-code>
<location>/error.html</location>
</error-page>

How should I deal with it? I've tried to create variable, like

STR='<error-page>
<error-code>400</error-code>
<location>/error.html</location>
</error-page>'

and use it

s/<\/web-app/"$STR" &/

but result is incorrect. Do I define var incorrectly? Is it possible to have such var with multinelines? How can I insert all these lines before ? Can it be done more simple with sed?

William Pursell · Accepted Answer · 2012-06-27T18:25:45.490

2

There are two issues. One, your string contains '/' characters, so you should use a different delimiter. Two, the newlines are problematic. You could do:

 $ STR2=$( echo "$STR" | sed 's/$/\\n/' | tr -d '\n' )
 $ sed "s@</web-app@$STR2 &@"

The assignment to STR2 simply replaces all newlines with \n, and works in bash. In zsh, some word splitting is happening that makes STR2 the same as STR.

edited Jun 27 '12 at 18:25

answered Jun 27 '12 at 18:17

William Pursell

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score 2 · Answer 2 · answered Jun 27 '12 at 18:25

2

You can try

/bin/ex your.xml << EDIT
/<\/web-app>
i
<error-page>
<error-code>400</error-code>
<location>/error.html</location>
</error-page>
.
x
EDIT

answered Jun 27 '12 at 18:25

pizza

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What for "." is used? exit text input mode? – Francheska Jun 28 '12 at 11:31

score 1 · Answer 3 · answered Jun 27 '12 at 17:57

1

Crude but effective:

sed '/<\/web-app>/i<error-page>\n<error-code>400</errorcode>\n<location>/error.html</location>\n</error-page>' filename

answered Jun 27 '12 at 17:57

Beta

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score 1 · Answer 4 · answered Jun 27 '12 at 18:38

1

The problem is that STR contains newlines which ed will interpret that as commands. I would suggest putting the content of STR into a file and use r to read it in. For example:

echo -ne '/<\/web-app/-1r OTHER_FILE\nw\n' | ed -s FILE_TO_MODIFY

answered Jun 27 '12 at 18:38

Thor

45,082
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score 0 · Answer 5 · answered Jun 28 '12 at 05:12

This might work for you:

STR='<error-page>\
<error-code>400</error-code>\
<location>/error.html</location>\
</error-page>'
echo -e '...\n</web-app>\n...' | sed '/<\/web-app>/i\'"$STR"
...
<error-page>
<error-code>400</error-code>
<location>/error.html</location>
</error-page>
</web-app>
...

To edit a file in place:

sed -i '/<\/web-app>/i\'"$STR" file

Trying to modify file with shell script - with /bin/ex

5 Answers5