Do you know this command in Bash?

[tseliot]

Hi, I'm a newbie in bash (and in programming in general) and I would like to know how I can replace some words with other ones in a text file without opening it with an editor.

For example I would like to change every "ciao" word in "text.txt" with an "hello" word and then either save the modified file or redirect the output to another file.

Is there a command (in bash) which does this?

Thanks in advance.

Alberto

[alamba]

Yes there is, I believe you can do this using pipes. Its pretty trivial. Unfortunately I'm not good at this. Try google for bash pipes if u're in a hurry or I'm sure someone would be able to give you the exact command here.

Akshay

[toojays]

There is no command built into bash to do this. However, the sed program was designed to do what you want.

To redirect the output to another file, you would run "sed -e 's/ciao/hello/g' input.txt >output.txt"

To save the modified file, you would use a special GNU extension: "sed -ie 's/ciao/hello/g' input.txt"

You can read the complete sed documentation online (http://www.gnu.org/software/sed/manual/sed.html), or in Emacs' info mode, or by running "info sed".

[tseliot]

There is no command built into bash to do this. However, the sed program was designed to do what you want.
...And the books I bought don't mention how to do this.


To redirect the output to another file, you would run "sed -e 's/ciao/hello/g' input.txt >output.txt"

To save the modified file, you would use a special GNU extension: "sed -ie 's/ciao/hello/g' input.txt"

You can read the complete sed documentation online (http://www.gnu.org/software/sed/manual/sed.html), or in Emacs' info mode, or by running "info sed".
Thanks I'll try it

EDIT: it WORKS GREAT! Thanks again now I can develop my little project!

[jerome bettis]

you can also use awk for this type of stuff. i prefer awk over sed cause it has C like syntax and sed is kinda bizarre. awk is pretty sweet check it out

cat input.txt | awk ' { gsub("oldtext", "nextext"); print $_ } ' > output.txt

[slavik]

or you can write perl :)

perl is sed, awk, shell, C all put in one. :)

it can also do db and stuff ... and a simple perl web server is like 10 lines of code ... take THAT apache and smoke it. :P

[sas]

In perl it'd be:
perl -pi -e 's/ciao/hello/g' text.txt

[Lord Illidan]

...And the books I bought don't mention how to do this.


Thanks I'll try it

EDIT: it WORKS GREAT! Thanks again now I can develop my little project!

What books have you got then? Am wondering what to buy myself..

[kvorion]

For example I would like to change every "ciao" word in "text.txt" with an "hello" word and then either save the modified file or redirect the output to another file.

Alberto

I think

perl -e `s/ciao/hello/g` > text.txt should work.

We are using Perl regular expressions here.

perl -e is simply to run the command on ur shell.
s/foo/bar/g;
replaces any occurrence of the exact character sequence foo in the "current string" by the character sequence bar; for example, foolish bigfoot would become barlish bigbart

[tseliot]

Thanks for the answers!

4 Lord Illidan: I'm using this book (I bought it on Amazon) "A Practical Guide to Linux Commands, Editors, and Shell Programming" - Mark Sobell

The other book of mine is: "Running Linux" Oreilly

BTW I haven't read them all.

[professor_chaos]

for bash scripting i find this a useful resource.
http://www.tldp.org/LDP/abs/html/