awk delete from end

AutoC · 10-23-2009, 01:24 AM

I have characters of the form "aa_b_c_d"

I need to repeatedly remove characters from the end,as in
if(aa_b_c_d) do
else if(aa_b_c) do
else if(aa_b) do
else if(aa) do
etc.

how can i do this in a script using awk..i just need to know how to split it like that..

ghostdog74 · 10-23-2009, 02:05 AM

don't understand what you trying to do. show a real example of an input, and show how you want the output to be.

AutoC · 10-23-2009, 03:34 AM

My inputs are of the form {cluster of characters}_{cluster of characters}_ etc...

eg. aa_bc_dd_ff etc.

Now, I should be able to repeatedly remove the final cluster of characters.

if i supply aa_bc_dd_ff i should get aa_bc_dd
if i supply aa_bc_dd i should get aa_bc
so on

hope thats clear

ghostdog74 · 10-23-2009, 04:03 AM

Code:

$ a="aa_bc_dd_ff"
$ echo "${a%_*}"
aa_bc_dd
$ a="aa_bc_dd"
$ echo "${a%_*}"
aa_bc

David the H. · 10-23-2009, 08:09 AM

What your really asking is how have awk print a range of fields; and apparently it's not a particularly easy thing to do. I found this page that discusses it:

http://awk.freeshell.org/RangeOfFields

Unfortunately, it looks like the final link on the page for more suggestions is dead, though.