Help with sed!? (RTFF,RTFM I hear you cry.......)

[Charles Harris]

Dear all,

Quick question:-

Sed. I'm sure in my glory days, I used to use sed to do text replacement on files (nothing wrong so far)....but here's the clintcher.. without writing the stdout to another file or did I? - ie replacing something within a file without creating a new version via redirection of stout.

Any tips pointers warmly received as ever, even RTFM's although if I trawl another sed how-to I might explode.

Cheers,

-ChaZ-

[Praveen Bezawada]

Hi
with sed you cannot do text replacement inline :(. you have to use perl

...BPK...

[Tom Geudens]

Hi,
Without an intermediate file ... I don't think that's possible in a script. Closest I could get was
(sed 's/Hallo/hallo/' < file1 > /tmp/file1) && (cat /tmp/file1 > file1) && (rm -f /tmp/file1)

... which is not at all what you asked ...
Tom Geudens :-(

[harry d brown jr · Accepted solution]

Not really an issue:

for small files under 16k:

sed -e "s/oldstr/newstr/g" filename|tee >filename

for larger files, cheat:

dd if=filename bs=3000000|sed -e "s/oldstr/newstr/g" > filename

of course adjust the "bs" (block size accordingly to input file size)

live free or die
harry

[Charles Harris]

Thanks for the reply's I cunningly dual posted this question with the wonder that is netscape and have received both your and their great reply's.


Thanks again!

-ChaZ-
Ps. I'll dish the points when netscape is back upto speed!

[Marco Paganini]

Hello Charles,

You cannot do it with sed. SED is the "Stream" ED. If you want to replace 'in place' you'll have to pipe commands to ed, like this:

echo "1,$ s/oldstring/newstring
w /tmp/testfile
q" | ed /tmp/testfile

This will change oldstring by newstring on /tmp/newfile

Regards,
Paga

[Stefan Schulz]

HI,

i don't think you can do it with sed. but i solved this problem with ex:

ex file_to_edit << EOF
1,\$s/oldstring/newstring/
w
q
EOF


Hope this helps

Regards Stefan