$ cat file.txt
one
two
three
$ cat file.txt | sed "s/one/1/"
1
two
Where is the word "three"?
UPDATED: There is no line after the word "three".
views:
130answers:
5
+1
A:
I guess there is no new line character after last line. sed didn't find line separator after last line and ignore it.
Update
I suggest you to rewrite this in perl (if you have it installed):
cat file.txt | perl -pe 's/one/1/'
Ivan Nevostruev
2010-03-03 16:45:50
You are correct - there is no new line character. But I cannot control this file - new line can be at the end but someone can remove it. And I need to process both of these cases.
Vladimir Bezugliy
2010-03-03 16:47:38
It should work either way.
Wooble
2010-03-03 16:48:18
That was my guess, too, but I just tested it on a file that had no line separator at the end -- the second E of THREE was the last character in the file -- and my version of sed dealt with it just fine. I'm using GNU sed version 4.1.5
shoover
2010-03-03 16:48:26
@Wooble But it does not work :(
Vladimir Bezugliy
2010-03-03 16:49:56
@shoover I use sed from AIX 5.3
Vladimir Bezugliy
2010-03-03 16:50:34
@Vladimir `perl` should fix it. If you can use it. See update
Ivan Nevostruev
2010-03-03 16:53:15
Unfortunately I cannot use perl.
Vladimir Bezugliy
2010-03-03 17:02:38
+2
A:
As Ivan suggested, your text file is missing the end of line (EOL) marker on the final line. Since that's not present, three is printed out by sed but then immediately over-written by your prompt. You can see it if you force an extra line to be printed.
sed 's/one/1/' file.txt && echo
This is a common problem since people incorrectly think of the EOL as an indication that there's a following line (which is why it's commonly called a "newline") and not as an indication that the current line has ended.
jamessan
2010-03-03 16:51:45
I need something like "sed 's/one/1/' file.txt > newfile.txt". But it does not work with "echo".
Vladimir Bezugliy
2010-03-03 17:03:25
That should work just fine. Sed's still printing out the `three` line. You just don't see it when you run interactively because of the prompt. Since it's still being printed out, redirecting to a file means the newfile will have that line.
jamessan
2010-03-03 17:08:54
Vladimir Bezugliy
2010-03-03 17:16:55
No, the echo was just for demonstration purposes. It forced a blank line to be printed when you ran the command interactively in order to separate the `three` line from your prompt but it has no bearing on how sed actually works. After running `sed 's/one/1/' file.txt > new_file.txt`, just open new_file.txt with your editor. You should see all three lines.
jamessan
2010-03-03 17:30:58
A:
Instead of cat'ing the file and piping into sed, run sed with the file name as an argument after the substitution string, like so:
sed "s/one/1/" file.txt
When I did it this way, I got the "three" immediately following by the prompt:
1
two
three$
GreenMatt
2010-03-03 17:06:38
+1
A:
A google search shows that the man page for some versions of sed (not the GNU or BSD versions, which work as you'd expect) indicate that it won't process an incomplete line (one that's not newline-terminated) at the end of a file. The solution is to ensure your files end with a newline, install GNU sed, or use awk or perl instead.
Wooble
2010-03-04 01:39:49