replacing word for word

Smokey · 01-20-2006, 09:57 AM

I have a text file and I would like to replace a name for another, the name is Daniel and I would like to replace all instances of Daniel for Danny. how can I do this automatically with a command?

tuxrules · 01-20-2006, 10:24 AM

Use Sed,

Code:

sed `s/Daniel/Danny/` filename.txt

Remember that sed does not alter the original file, it just displays the modified output. If you want to put the output in a new file, use bash output redirection.

Code:

sed `s/Daniel/Danny/` filename > newfile

Tux,

druuna · 01-20-2006, 10:27 AM

Hi,

There are more then one way to do this, here's one using sed:

sed -i.bak 's/Daniel/Danny/g' <textfile>

The s (sed -i.bak 's/Daniel/Danny/g' <textfile>) tells sed that you want to replace, the g on the end makes it global, not just the first one on a line.
sed looks for Daniel (sed -i.bak 's/Daniel/Danny/g' <textfile>),
and put Danny (sed -i.bak 's/Daniel/Danny/g' <textfile>) in its place.

The -i.bak option makes a copy of the original named <textfile>.bak, changes are made in <textfile>

Hope this helps.

tuxrules · 01-20-2006, 10:40 AM

Quote:

Hi,

There are more then one way to do this, here's one using sed:

sed -i.bak 's/Daniel/Danny/g' <textfile>

I may be wrong as I am still learning sed but isn't the g option in sed irrelevant. As far as I know, g switch is used for global and sed by default does global changes. g switch is needed for ed(sed's ancestor), which by default only changes the current line. Sed on the other hand changes all the lines by default.

Tux,

druuna · 01-20-2006, 10:58 AM

Hi,

You do need the g if you want to change multiple on the same line (global for that line):

cat infile
Daniel aap noot Daniel

sed 's/Daniel/Danny/' infile
Danny aap noot Daniel

sed 's/Daniel/Danny/g' infile
Danny aap noot Danny

Cannot find this in the manpage, but the Sed&Awk book from O'Reilly (page 80 if you have a copy) also states that 'Normally only the first occurence is replaced.'.

Hope this clears things up.

tuxrules · 01-20-2006, 11:52 AM

Quote:

Originally Posted by druuna

Hi,

You do need the g if you want to change multiple on the same line (global for that line):

cat infile
Daniel aap noot Daniel

sed 's/Daniel/Danny/' infile
Danny aap noot Daniel

sed 's/Daniel/Danny/g' infile
Danny aap noot Danny

Cannot find this in the manpage, but the Sed&Awk book from O'Reilly (page 80 if you have a copy) also states that 'Normally only the first occurence is replaced.'.

Hope this clears things up.

Awesome...thanks buddy. As I said, I am still learning. I have that Sed & Awk (O'Reilly) book and now that you've told me I think I remember it. Anyway, I better get back to that book

. Thanks for clearing that up.

Tux,

pixellany · 01-20-2006, 02:58 PM

I hasten to point out that almost any text editor or word processor has a search and replace function.
CLI is NOT always the easiest way to do something---although you will certainly learn more that way.