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Finding a String and Replacing it with an incremental value

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# 1  
Old 11-09-2010
Finding a String and Replacing it with an incremental value
Hi Friends,

I have a text file which has about 200,000 records in it. we have a string which repeats in each and every record. So we have to write a script in ksh which finds that string on each line and replaces it with a new string(incremental value) for a set every four records.

To be more clear please look at the sample data below

say file a.txt has some 8 records in it
Code:
dallastexasabc12345tx
dentonabc12345tx
houstoabc12345tx
sanfraabc12345tx
oklahamaabc12345oh
irvingfrabc12345tx
mcaurtabc12345tx
kingkotabc12345tx

abc12345 is the repeating string in each and every record, we have to replace it with an incremental value say 12345678 in first four records and then with 12345679 in the next four records and so on.

Any help is greatly appreciated.
Thank you.
Moderator's Comments:
Mod Comment
Please use code tags
Last edited by vgersh99; 11-09-2010 at 01:00 PM.. Reason: Code tags, please!
# 2  
Old 11-09-2010
This works for me in ksh88

Code:
typeset -i cnt=1
typeset -i seq=678
cat /dev/null > newfile.txt
while read string
do
echo $string | sed -e "s/\(.*\)\(12345\)\(.*\)/\1\2$seq\3/" >> newfile.txt
((cnt%4 == 0)) && seq=$((seq+1))
cnt=$((cnt+1))
done < mod.txt

Your input in "mod.txt"

Code:
dallastexasabc12345tx
dentonabc12345tx
houstoabc12345tx
sanfraabc12345tx
oklahamaabc12345oh
irvingfrabc12345tx
mcaurtabc12345tx
kingkotabc12345tx

Was changed to

Code:
dallastexasabc12345678tx
dentonabc12345678tx
houstoabc12345678tx
sanfraabc12345678tx
oklahamaabc12345679oh
irvingfrabc12345679tx
mcaurtabc12345679tx
kingkotabc12345679tx

in "newfile.txt"
# 3  
Old 11-09-2010
Instead of replacing whole string abc12345 with 12345678 and so on it is adding 678 at the end of the string.
Input file mod.txt
Code:
 
dallastexasabc12345tx
dentonabc12345tx
houstoabc12345tx
sanfraabc12345tx
oklahamaabc12345oh
irvingfrabc12345tx
mcaurtabc12345tx
kingkotabc12345tx

It should actually look like:
newfile.txt
Code:
dallastexas12345678tx
denton12345678tx
housto12345678tx
sanfra12345678tx
oklahama12345679oh
irvingfr12345679tx
mcaurt12345679tx
kingkot12345679tx

Last edited by vpv0002; 11-09-2010 at 03:17 PM..
# 4  
Old 11-09-2010
Code:
awk -v var=12345678 '
NR>1 && NR%4==1 {var++}
{
  s1=s2=$0
  sub("[0-9].*","",s1)
  sub(".*[0-9]","",s2)
  print s1 var s2
}'  file

# 5  
Old 11-09-2010
Missed the 'abc' part, sorry. It's a simple fix.

Code:
typeset -i cnt=1
typeset -i seq=678
cat /dev/null > newfile.txt
while read string
do
echo $string | sed -e "s/\(.*\)\(abc12345\)\(.*\)/\112345$seq\3/" >> newfile.txt
((cnt%4 == 0)) && seq=$((seq+1))
cnt=$((cnt+1))
done < mod.txt

# 6  
Old 11-09-2010
bash code:
  1. #!/bin/bash
  2. i=12345678
  3. while :
  4. do
  5.    for i in {1..4}
  6.    do read || break 2
  7.       echo ${REPLY/abc12345/$i}
  8.    done
  9.    ((i++))
  10. done <file-in >file-out
Last edited by frans; 11-09-2010 at 04:25 PM..
# 7  
Old 11-09-2010
Also, got to thinking about the 200,000 lines you have. Might want to avoid extra processes and not use sed inside a loop. May not make a difference, but the following works and does take less system resources/time (fractions of a second) on my system:

Code:
typeset -i cnt=1
typeset -i seq=678
AL_CONST=abc12345
NM_CONST=12345
cat /dev/null > newfile.txt
while read orig_str 
do
  left_str=${orig_str%%${AL_CONST}*}
  rght_str=${orig_str##*${AL_CONST}}
  new_str="${left_str}${NM_CONST}${seq}${rght_str}"
  echo $new_str >> newfile.txt
  ((cnt%4 == 0)) && seq=$((seq+1))
  cnt=$((cnt+1))
done < mod.txt
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