UNIX for Dummies Questions & Answers

How would I delete white spaces in a specified file?

Also, I'd like to know what command I would use to take something off a regular expression, and put it onto another.
ie.
.
.
.
expression1 <take_off>
.
.
.
expression2 (put here)
.
.
.
Any help would be great, thanks!

For the first part, please search the forums for removing or deleting whitespace (blank lines, etc)... many people have asked this, such as here:

https://www.unix.com/shell-programming-and-scripting/11400-remove-whitespace-test.html?s=
https://www.unix.com/shell-programming-and-scripting/10336-removing-whitespace-files.html?s=
https://www.unix.com/shell-programming-and-scripting/11770-leading-trailing-spaces.html?s=

And many, many others!

As for the second, I kinda have an idea of what you're talking about, but I'm not entirely sure. Post a concrete example of what you're trying to do... just remove a few words off the end of one sentence and paste them on the end of another?

Ok, this is what I'm trying to do
--------------------------------------------------------------------
before:
...
...
<unique expression1 here> XXX
...
...
...
<another unique expression2 here>
...
...
---------------------------------------------------------------------
after:
...
...
< unique expression1 here>
...
...
...
<another unique expression2 here> XXX
...
...

you can define the befor or after text. you have to know what your looking for befor you can look for it.

IE: /text_befor_uniq_regx[REGEX](textafter REGEX)rest_of_line/
$save=$1;
/(text_befor_uniq_regx[REGEX])/$1 $save/

something like that.

Like Optimus_P said ... how do you know where in the file you want to delete text and where you want to insert it?

Because we need to identify where <unique expression1 here> is and then grab the text after that; then identify where <another unique expression2 here> is and insert the text we grabbed.

But will expression2 always come after expression1?

Oh, i'm sorry, you know what the unique expressions are.

Try this code. It's inefficient and makes four passes on the file (one for grep and three for sed), but:

Code:

express1="first expression you search for"
express2="second expression you search for"

tomove=`grep "^$express1" myfile | sed 's/^'$express1'//'`

sed 's/^'$express1$tomove'/'$express1'/' myfile > tmpfile

sed 's/^'$express2'/'$express2$tomove'/' tmpfile > myfile