How to escape special characters in long sed string

Question

I have this string that I want to include at line 115 of a file, using sed. However, it always complains on some unknown command. I have followed other solutions in other questions, but haven't managed to solve it.

sed '115"<"img src="\.\/index_files\/Logo\.png" width="200" height="160" align="right" border="0">"' index.html > test.html

Thanks!

Answer 1

Because " is not a sed command. As it says in the error message, though not very clearly.

The address 115 has to be followed by a sed command, probably i

• Then get rid of some of the "s. The ones around the < and after the >
• Then don't escape the /s, they don't need escaping.
• Then don't escape anything as i command just takes text.

This left we with: sed '115 i <img src="./index_files/Logo.png" width="200" height="160" align="right" border="0">'

Answer 2

User richard describes very well what's wrong with your sed command, and also gives the correct editing script to perform the action you're attempting.

I'm giving an alternative approach which will work in a number of different cases:

The sed command r will insert the contents of a file at the current position in the data stream.

Your sed command line could be written

$ sed '115r /dev/stdin' index.html <data.in

which would have the same effect as sed '115r data.in' index.html... if the data that you wanted to insert after line 115 was stored in the file data.in.

/dev/stdin is a special file that contains whatever is sent through the standard input.

You could also do (with shells supporting "here-strings"):

$ sed '115r /dev/stdin' index.html <<<"my string of stuff"

or

$ sed '115r /dev/stdin' index.html <<<"$myvariableofwonder"

This also works as expected with piping from other commands, obviously:

$ sed -n '1,10p' myfile | sed '115r /dev/stdin' index.html

This will transplant lines 1 to 10 of myfile into index.html at line 115.