UNIX for Dummies Questions & Answers

In a file, field separetor in line is irregular number of spaces, so I canot use field in sub function to get my charecter replaced with empty space. I would like to substitute only one perticular charecter with space at perticular posiotn, so I canot use perticular character as that may occur before the position to be repalced. I have written the code as below but passing (/substr($0,39,1)/ to sub function is wrong. Plz suggest any alternatives for below code.

awk '{ if(substr($0,39,1)=="N") { sub(/substr($0,39,1)/," ",$0); printf "%-517s", $0" ABCD ";} }' < inputfile >

Show an example for input and desired output please.

Input:
NICEP H030325 350160564A N717391601 25081117201000199 11/13/200811/13/2008 496

Output:

NICEP H030325 350160564A 717391601 25081117201000199 11/13/200811/13/2008 496 ABCD

Code:

root@isau02:~> echo "NICEP H030325 350160564A N717391601 25081117201000199 11/13/200811/13/2008 496 "| awk '$4 ~ /^[A-Z]/ {sub(/^./,"",$4); print}'
NICEP H030325 350160564A 717391601 25081117201000199 11/13/200811/13/2008 496

thanks a lot, but we can not use $4 as field separator is not single space all the times..can we send any index(position) as an argument to sub function....

If this works for your input file, you can use sub/substr as you did in your example if it is always at some fix position. If you show examples of any other posibilites of which field is the one you need to be changed, maybe post more examples of posibilities.

It is working and I have modified as per your suggestion. I am almost done.
I am able to run the following code blocks independently. If I try to make them as one, I am getting error always at 2nd block. Can you please suggest what syntax error causing this?

ErrorLog:The error context is
substr($0,39,1)=="N" || substr($0,39,1)=="X" || substr($0,39,1)=="A" >>> { <<< # For the letters N, X, A
awk: 0602-502 The statement cannot be correctly parsed. The source line is 20.

3 AWK logical blocks:

------------------
BEGIN {
if (length($0) > 500) {
if (substr($0,39,1)=="X" || substr($0,39,1)=="A"){
space=" ";
sub( substr($0,39,1) , space)
printf "%-517s\n", $0
}
else {

printf "%-517s\n", $0

}
}
}
-------------

BEGIN {a["N"]="N ABC";a["X"]="P ABC";a["A"]="D ABC"}
substr($0,39,1)=="N" || substr($0,39,1)=="X" || substr($0,39,1)=="A" { # For the letters N, X, A
val=substr($0,39,1);
space=" ";
sub( substr($0,39,1) , space)
printf "%-517s\n", $0 " " a[val]
}

----------------------

BEGIN{ s=substr($0,39,20); sub(/ *$/, "", s) # s = trimmed string of pos 39-58 for other letters
if(length(s)==9) {
printf "%-517s\n", $0 " ABC EFG"
}
else if(length(s)==16) {
printf "%-517s\n", $0 " DEF GHI"
}
else {
printf "%-517s\n", $0 " JKL MNO"
}
}