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Search for a string and replace the searched string in the same position in samefile

 
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Top Forums UNIX for Dummies Questions & Answers Search for a string and replace the searched string in the same position in samefile
# 8  
Old 03-02-2009
Quote:
Originally Posted by Whiteboard
Code:
$ cat tab.txt
00000000 0 +00000000.00 2008/12/29 11:06:04 0108/12/29 10:05:37 00521363
 
$ awk '{sub(/^../,"20",$6); print}' OFS="\t" tab.txt
00000000        0       +00000000.00    2008/12/29      11:06:04        2008/12/29      10:05:37        00521363

$ cat samp.txt
00000000        0       +00000000.00    2008/12/29      11:06:04        0108/12/29

$ awk '{sub(/^../,"20",$6); print}' samp.txt
00000000 0 +00000000.00 2008/12/29 11:06:04 2008/12/29

$ awk '{sub(/^../,"20",$6); print}' OFS="\t" samp.txt
00000000        0       +00000000.00    2008/12/29      11:06:04        2008/12/29


Hope you can understand the above code with sample examples.....
White your suggestion worked fine ;-) ...Thanks
But my file contains header records i.e first 3 to 4 rows are column headings..so when i apply your above mentioned command it applies to the column heading row also..is there any provision to skip the first 3 to 4 lines and then do the required manipulation...i don not want to read the file line by line .i just want to skip the first three to four lines and do the date manipulation part,write it in file and then move it to the original file. Pls help me out....
# 9  
Old 03-02-2009
If you want to skip first 3 lines of your file...

Code:
$ cat samplefile
No  unit  country
1   54    belgium
2   87    colombia
3   666   peru
4   432   dubai
5   987   japan
 
$ awk 'NR>3 {print $0}' samplefile
3   666   peru
4   432   dubai
5   987   japan

NR>3- this command will take care of your requirement... Play with that command according to your requirement...
# 10  
Old 03-02-2009
Quote:
Originally Posted by Whiteboard
If you want to skip first 3 lines of your file...

Code:
$ cat samplefile
No  unit  country
1   54    belgium
2   87    colombia
3   666   peru
4   432   dubai
5   987   japan
 
$ awk 'NR>3 {print $0}' samplefile
3   666   peru
4   432   dubai
5   987   japan

NR>3- this command will take care of your requirement... Play with that command according to your requirement...
Explain your command white...what each part stands for ???
# 11  
Old 03-02-2009
NR means No of records...

Code:
NR>3 will start listing from the 4th line till end of file

Code:
$0 will list complete file... $1 represents 1st column, $2 represents 2nd column and so on...

# 12  
Old 03-02-2009
MySQL
Quote:
Originally Posted by Whiteboard
NR means No of records...

Code:
NR>3 will start listing from the 4th line till end of file

Code:
$0 will list complete file... $1 represents 1st column, $2 represents 2nd column and so on...

Thanks once again saviour ;-) SmilieSmilie
# 13  
Old 03-13-2009
awk '{sub(/^../,"20",$6); print}' infile > tmpfile
This will replace the first two digits in "coulmn 6" as "20"
White if i want to replace the first two digits with the same "20" in other columns also,in the same command,how do i do it. I tried

head -8 $file1 | awk '{sub(/^01/,"20",$1); print}' | awk '{sub(/^01/,"20",$2); print}' | awk '{sub(/^01/,"20",$3); print}' > file2.txt

but only the first two columns are getting modified while the 3rd column does not.why is the third pipeline not working??
is there any command to make the above 3 changes( i mean can we modify 2 or more columns by replacing the first two characters alone) in the same command itself without increasing the temporary files being created to hold the modified values (like file1.txt,file2.txt...)
Pls help
# 14  
Old 03-13-2009
Code:
nawk -v cols='1 2 3'  'BEGIN {n=split(cols, colsA, FS)} {for(i=1; i<=n; i++) sub(/^01/,"20",$colsA[i]); print}' $file1

 
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