cut command --complement flag equivalent in AWK - unix

Question

I am new to writing shell scripts
I am trying to write an AWK command which does exactly the below
cut --complement -c $IGNORE_RANGE file.txt > tmp
$IGNORE_RANGE can be of any value say, 1-5 or 5-10 etc
i cannot use cut since i am in AIX and AIX does not support --complement, is there any way to achieve this using AWK command
Example:
file.txt
abcdef
123456
Output
cut --complement -c 1-2 file.txt > tmp
cdef
3456
cut --complement -c 4-5 file.txt > tmp
abcf
1236
cut --complement -c 1-5 file.txt > tmp
f
6

Answer 1

Could you please try following, written and tested with shown samples. We have range variable of awk which should be in start_of_position-end_of_position and we could pass it as per need.
awk -v range="4-5" '
BEGIN{
split(range,array,"-")
}
{
print substr($0,1,array[1]-1) substr($0,array[2]+1)
}
' Input_file
OR to make it more clear in understanding wise try following:
awk -v range="4-5" '
BEGIN{
split(range,array,"-")
start=array[1]
end=array[2]
}
{
print substr($0,1,start-1) substr($0,end+1)
}
' Input_file
Explanation: Adding detailed explanation for above.
awk -v range="4-5" ' ##Starting awk program from here creating range variable which has range value of positions which we do not want to print in lines.
BEGIN{ ##Starting BEGIN section of this program from here.
split(range,array,"-") ##Splitting range variable into array with delimiter of - here.
start=array[1] ##Assigning 1st element of array to start variable here.
end=array[2] ##Assigning 2nd element of array to end variable here.
}
{
print substr($0,1,start-1) substr($0,end+1) ##Printing sub-string of current line from 1 to till value of start-1 and then printing from end+1 which basically means will skip that range of characters which OP does not want to print.
}
' Input_file ##Mentioning Input_file name here.

Answer 2

You can do this in awk:
awk -v st=1 -v en=2 '{print substr($0, 1, st-1) substr($0, en+1)}' file
cdef
3456
Or:
awk -v st=4 -v en=5 '{print substr($0, 1, st-1) substr($0, en+1)}' file
abcf
1236