regex help needed 1

[sbrews]

I have a variable that has several items in it seperated by a space:

JUNK="item1 item2 item3"
echo $JUNK
item1 item2 item3

Depending on input from the user (via a script), I may need to remove any number of those "items" AND still leave once space between them:

echo $JUNK | *** magical sed command that is eluding me ***
item1 item2 or output could be
item1 item3 or
item2 item3 or
item3 etc. depending what what as entered via the user.

I have been able to match and remove beginning, middle and end leaving 1 space between (if needed), but not all of the above. To restate that in another way - I need to be able to find itemX anywhere in the string and remove it.

Any help would be greatly appreciated.

 

[olded]

Well, it ain't pretty, but you can do something like this:

Space out the variable that you want to keep. This leaves item2:

JUNK="item1 item2 item3"
string1="1"
string2=" "
string3="3"

echo $JUNK| sed 's/item['"${string1}"'] //' |sed 's/item['"${string2}"'] //'|sed 's/item['"$
{string3}"']//'

This leaves item1 & item3

string1=" "
string2="2"
string3=" "

echo $JUNK| sed 's/item['"${string1}"'] //' |sed 's/item['"${string2}"'] //'|sed 's/item['"$
{string3}"']//'

Maybe somebody smarter can come up with a better idea.

 

[Ygor]

Perhaps you could use cut...

$ echo $JUNK
item1 item2 item3
$ echo $JUNK | cut -d ' ' -f 1,2
item1 item2
$ echo $JUNK | cut -d ' ' -f 3
item3

 

[Ygor]

Or you can use bash to remove matched strings from a variable, e.g...

$ JUNK="item1 item2 item3"
$ JUNK=${JUNK//item2/}
$ echo $JUNK
item1 item3
$ JUNK=${JUNK//item3/}
$ echo $JUNK
item1

 

[p5wizard]

use tr to convert to 1 string per line
grep -v the unwanted string
use tr to convert to strings on one line

$ JUNK="item1 item2 item3"
$ echo $JUNK
item1 item2 item3
$ ITEM=item2
$ JUNK=$(echo $JUNK|tr ' ' '\n'|grep -v $ITEM|tr '\n' ' ')
$ echo $JUNK
item1 item3

undoubtedly it can be coded in sed also...


HTH,

p5wizard

 

[sbrews]

ygor - that works great on newer versions of KSH or bash. unfortunately, I have an older version of KSH and that particular substitution doesnt work - which is a shame as it would have been the ideal solution.

p5wizard - that works perfectly. A star for you.