problem with sed

eradev · 05-03-2010, 11:18 AM

Hello,

Could you help me with a sed command to add a text before line number in text file ?
I have text file with 500 lines, and i want to add 3 more lines with text after line 300, OR before line 302, isn't no problem.

Regards,
Eduard

MTK358 · 05-03-2010, 11:34 AM

I don't really understand your question, but as far as I can tell you want to insert some text after line 300?

Code:

sed -r '300 s:.*:&\nthis text will be inserted after line 300:'

Use \n to insert a newline, and \\ for a literal backslash.

eradev · 05-03-2010, 11:44 AM

machine# sed -r '300 s:.*:&\nthis text will be inserted after line 300:' config-test > config-test1
sed: illegal option -- r
usage: sed script [-Ealn] [-i extension] [file ...]
sed [-Ealn] [-i extension] [-e script] ... [-f script_file] ... [file ...]

You understand me correct. I want to insert some text after line 300.
And in other case i want to insert some text before line 100
I need help with theese two commands

crts · 05-03-2010, 11:45 AM

Code:

sed -e '300 a\
Add this line after line 300' inputfile > outputfile

Code:

sed -e '300 i\
Add this line before line 300' inputfile > outputfile

MTK358 · 05-03-2010, 11:50 AM

The -r flag means "extended regular expressions". I find then better looking and easier to use. Maybe your version of sed just doesn't support it.

eradev · 05-03-2010, 11:57 AM

Quote:

Originally Posted by crts

Code:

sed -e '300 a\
Add this line after line 300' inputfile > outputfile

Code:

sed -e '300 i\
Add this line before line 300' inputfile > outputfile

yep, i tried this before..

Code:

machine# sed -e '300 a\
? Add this line after line 300' config-test > config-test1
sed: 1: "300 a
Add this line aft ...": command a expects \ followed by text
machine# sed -e '300 a\ Add this line after line 300' config-test > config-test1
sed: 1: "300 a\ Add this line af ...": extra characters after \ at the end of a command
machine# sed -e '300 i\
? Add this line before line 300' config-test > config-test1
sed: 1: "300 i
Add this line bef ...": command i expects \ followed by text
machine#
machine# sed -e '300 i\ Add this line before line 300' config-test > config-test1
sed: 1: "300 i\ Add this line be ...": extra characters after \ at the end of i command
machine#

The OS is 7.2-RELEASE FreeBSD

crts · 05-03-2010, 12:04 PM

Quote:

Originally Posted by eradev

yep, i tried this before..

Code:

machine# sed -e '300 a\
? Add this line after line 300' config-test > config-test1
sed: 1: "300 a
Add this line aft ...": command a expects \ followed by text
machine# sed -e '300 a\ Add this line after line 300' config-test > config-test1
sed: 1: "300 a\ Add this line af ...": extra characters after \ at the end of a command
machine# sed -e '300 i\
? Add this line before line 300' config-test > config-test1
sed: 1: "300 i
Add this line bef ...": command i expects \ followed by text
machine#
machine# sed -e '300 i\ Add this line before line 300' config-test > config-test1
sed: 1: "300 i\ Add this line be ...": extra characters after \ at the end of i command
machine#

The OS is 7.2-RELEASE FreeBSD

It is important that there is no space after \. Also, which version of sed are you using?

Can you try

Code:

machine# sed -e '300 a\Add this line after line 300' config-test > config-test1

eradev · 05-03-2010, 12:04 PM

Quote:

Originally Posted by MTK358

The -r flag means "extended regular expressions". I find then better looking and easier to use. Maybe your version of sed just doesn't support it.

Without -r flag it's work, but \n isn't insert new line..

crts · 05-03-2010, 12:06 PM

Quote:

Originally Posted by eradev

Without -r flag it's work, but \n isn't insert new line..

Then it is probably your sed version because on my system MTK358's solution also worked.

eradev · 05-03-2010, 12:13 PM

yes, probably, but \n isn't insert new line and I have to write 3 lines

crts · 05-03-2010, 12:26 PM

Quote:

Originally Posted by eradev

yes, probably, but \n isn't insert new line and I have to write 3 lines

Ok, I do not like workarounds but since you have a 'weird' version of sed consider this workaround:

Code:

sed -n '1,300 p' input > tmp1
sed -n '301,$ p' input > tmp2
cat > insert_file << EOF
first line to be inserted after line 300
second line to be inserted after line 300
third line to be inserted after line 300
EOF
cat tmp1 insert_file tmp2 > finalout

pixellany · 05-03-2010, 12:45 PM

eradev;
You said you are using BSD. This reinforces the suggestion that you might have a different version of SED than what we are used to. What version are you using?

MTK358 · 05-03-2010, 01:29 PM

\n does mean "newline" in sed (GNU sed, at least), just as it does in the C programming language.

If your sed is not GNU sed (which is standard for Linux), then we don't really know how to use it.

pixellany · 05-03-2010, 01:43 PM

http://www.grymoire.com/Unix/Sed.html (not written for gnu SED)
"\n" means newline here also....BUT:

When entering things in "real time" in a terminal, you use "\" to escape the newline that does not appear--eg

somecommand -flags arguments \
more arguements

I wonder if that is relevant to OP's issue?

petrus4 · 05-04-2010, 09:56 PM

Quote:

Originally Posted by eradev

Hello,

Could you help me with a sed command to add a text before line number in text file ?
I have text file with 500 lines, and i want to add 3 more lines with text after line 300, OR before line 302, isn't no problem.

Regards,
Eduard

The sed answers are cool, and truthfully I didn't know you could use sed like that, but I would have used ed.

Code:

ed <file>
302i
This is the first line.
This is the second line.
This is the third line.
.
wq

It may seem strange, but I use ed quite a lot. I like it. I also feel that although it isn't really complicated, ed is sufficiently different to what you're used to, that if you want to learn to use it, you need to use it a lot in order to get familiar with it. Although I still use vi(m) for big files or longer edits, for me ed is very useful when I just want to do quick single line edits or search/replace for things; it's quicker than loading vi for that, and when you don't have to do much, the line addressing makes it a lot faster than vi's modal interface, as well.

Ed might also be better than sed in this case, because from what I've seen anywayz, sed isn't really designed to handle newlines. It can, but it's awkward.