Extract a string from another string in UNIX

Shell Programming and Scripting
1

I have a string

string="Please have a nice day and sleep well Replace_12123_31233_32134_12342 Good day"

How do i replace "Replace_12123_31233_32134_1234" in the above string.??

Please help.

Regards,
Qwerty

2

bash/ksh93:

$ string="Please have a nice day and sleep well Replace_12123_31233_32134_12342 Good day"

$ string=${string//Replace_12123_31233_32134_12342/REPLACED}

$ echo $string
Please have a nice day and sleep well REPLACED Good day
3

i do not require to replace that with "Replaced". i want to take out that string - "Replace_12123_31233_32134_12342" and do certain operations with it... this might be a different string everytime... but the position of the string wouldnt change..

4

Didn't you write "How do i replace "Replace_12123_31233_32134_1234" in the above string.??" earlier?

Please elaborate on this aspect. At what position will "this" string occur in the bigger string? Does "this" string terminate with a space/end-of-bigger-string? or does "this" string have a fixed length?