Quick sed question

aevangelica · 05-24-2006, 01:38 PM

Ioha,

I was just wondering if sed can write directly back to the file it reads from. As it stands, if i want to change foo to bar i do:

sed "s|foo|bar|g" $file > temp$file
mv temp$file $file

but that just seems wasteful to me. Thoughts?

dubz_444 · 05-24-2006, 01:39 PM

your way works...

this doesnt

cat bob.pa | sed 's/greg/sammy/g' > bob.pa

U can use your way for editing files that you want to keep the same name

pixellany · 05-24-2006, 10:55 PM

Quote:

Originally Posted by dubz_444

this doesnt

cat bob.pa | sed 's/greg/sammy/g' > bob.pa

Actually, the above works just fine---i just tried it.

dubz_444 · 05-25-2006, 02:47 AM

well, my file comes out empty!

vls · 05-25-2006, 03:02 AM

Quote:

Originally Posted by aevangelica

Ioha,

I was just wondering if sed can write directly back to the file it reads from. As it stands, if i want to change foo to bar i do:

sed "s|foo|bar|g" $file > temp$file
mv temp$file $file

but that just seems wasteful to me. Thoughts?

GNU sed version 4.0.9:

sed --help [drastically snipped]

Quote:

-i[suffix], --in-place[=suffix]
edit files in place (makes backup if extension supplied)

so
sed -ibak "s|foo|bar|g" $file outputs the modified file and creates file.bak(the original). No extension, no backup.

aevangelica · 05-25-2006, 10:55 AM

Excellent, thanks vls!