Shell – sed insert in the beginning of multiple files is not working

sedshell-script

I came across a lot of answers, including theses:

And I can't find a way to do what I want to do. I need to insert #encoding:utf-8 at the beginning of every .html.erb file of my directory (recursively). I tried using this command

find . -iname "*.erb" -type f -exec sed -ie "1i \#encoding:utf-8" {} \;

But it throws this error:

sed: 1: "1i #encoding:utf-8": extra characters after \ at the end of i command

Best Answer

To edit file in-place with OSX sed, you need to set empty extension:

$ sed -i '' '1i\
#encoding:utf-8' filename

And you need a literal newline after i\. This is specified by POSIX sed.

Only GNU sed allows text to be inserted on the same line with command.

sed can also works with multiple files at once, so you can use -exec command {} + form:

$ find . -iname "*.erb" -type f -exec sed -i '' '1i\
#encoding:utf-8' {} +

Related Solutions

Sed not working as intended

I guess I found the reason why.

If I put some blank after the filename, a filename with trailing blanks is searched. I can reproduce the problem this way:

Sources:

cat q.dat
Q
Not q
And Q again
And again not


cat kuh.dat 
Die dumme
Kuh

Working example with filename 'kuh.dat':

sed '/Q/{
s/Q//g
r kuh.dat
}' q.dat

Die dumme
Kuh
Not q
And  again
Die dumme
Kuh
And again not

Now the failing example, with 'kuh.dat '.

sed '/Q/{
s/Q//g
r kuh.dat 
}' q.dat

Not q
And  again
And again not

Since the filename isn't quoted, it is a great surprise for me, that the blank at the filename-end is recognized. And it isn't visible in the shell, so I searched for a long time without success, where the difference between the two examples is.

sed on OSX – How to Insert at a Certain Line

Strictly speaking, the POSIX specification for sed requires a newline after a\:

[1addr]a\
text
Write text to standard output as described previously.

This makes writing one-liners a bit of a pain, which is probably the reason for the following GNU extension to the a, i, and c commands:

As a GNU extension, if between the a and the newline there is other than a whitespace-\ sequence, then the text of this line, starting at the first non-whitespace character after the a, is taken as the first line of the text block. (This enables a simplification in scripting a one-line add.) This extension also works with the i and c commands.

Thus, to be portable with your sed syntax, you will need to include a newline after the a\ somehow. The easiest way is to just insert a quoted newline:

$ sed -e 'a\
> text'

(where $ and > are shell prompts). If you find that a pain, bash [1] has the $' ' quoting syntax for inserting C-style escapes, so just use

sed -e 'a\'$'\n''text'

[1] and mksh (r39b+) and some non-bash bourne shells (e.g., /bin/sh in FreeBSD 9+)

Best Answer

Related Solutions

Sed not working as intended

sed on OSX – How to Insert at a Certain Line

Related Question