I want to mask only the 2nd column of the data.
Input:
First_name,second_name,phone_number
ram,prakash,96174535
hari,pallavi,98888234
anurag,aakash,82783784
Output Expected:
First_name,second_name,phone_number
ram,*******,96174535
hari,*******,98888234
anurag,******,82783784
The sed program will do this just fine:
sed '2,$s/,[^,]*,/,*****,/'
The 2,$ only operates on lines 2 through to the end of the file (to leave the header line alone) and the substitute command s/,[^,]*,/,*****,/ will replace anything between the first and second comma with the mask *****.
Note that I've specifically used a fixed number of asterisks in the replacement string. Whether you're hiding passwords or anonymising data (as seems to be the case here), you don't want to leak any information, including the size of the names being replaced.
If you really want to use the same number of characters as in the original data, and you also want to cater for the possibility of replacing multiple fields, you can use something like:
awk -F, 'BEGIN{OFS=FS}NR==1{print;next}{gsub(/./,"*",$2);gsub(/./,"*",$4);print}'
This will also leave the first line untouched but will anonymise columns two and four (albeit with the information leakage previously mentioned):
echo 'First_name,second_name,phone_number,other
ram,prakash,96174535,abc
hari,pallavi,98888234,def
anurag,aakash,82783784,g
bob,santamaria,124,xyzzy' | awk -F, 'BEGIN{OFS=FS}NR==1{print;next}{gsub(/./,"*",$2);gsub(/./,"*",$4);print}'
First_name,second_name,phone_number,other
ram,*******,96174535,***
hari,*******,98888234,***
anurag,******,82783784,*
bob,**********,124,*****
Doing multiple columns with full anonymising would entail using $2="*****" rather than the gsub (for both columns of course).
Another in awk. Using gsub to replace every char in $2 with an *:
$ awk 'BEGIN{FS=OFS=","}NR>1{gsub(/./,"*",$2)}1' file
First_name,second_name,phone_number
ram,*******,96174535
hari,*******,98888234
anurag,******,82783784
try following too once and let me know if this helps you.
awk -F"," 'NR>1{$2="*******"} 1' OFS=, Input_file
Related
We have a requirement where we have a csv file with custom delimiter '||' (double-pipes) . We have 40 columns in the file and the file size is approximately between 400 to 500 MB.
We need to sort the file based on 2 columns, first on column 4 and then by column 17.
We found this command using which we can sort for one column, but not able to find a command which can sort based on both columns.
Since we use a delimiter with 2 characters, we are using awk command for sorting.
Command:
awk -F \|\| '{print $4}' abc.csv | sort > output.csv
Please advise.
If your inputs are not too fancy (no newlines in the middle of a record, for instance), the sort utility can almost do what you want, but it supports only one-character field separators. So || would not work. But wait, if you do not have other | characters in your files, we could just consider | as the field separator and account for the extra empty fields:
sort -t'|' -k7 -k33 foo.csv
We sort by fields 7 (instead of 4) and then 33 (instead of 17) because of these extra empty fields. The formula that gives the new field number is simply 2*N-1 where N is the original field number.
If you do have | characters inside your fields a simple solution is to substitute them all by one unused character, sort, and restore the original ||. Example with tabs:
sed 's/||/\t/g' foo.csv | sort -t$'\t' -k4 -k17 | sed 's/\t/||/g'
If tab is also used in your fields chose any unused character instead. Form feed (\f) or the field separator (ASCII code 28, that is, replace the 3 \t with \x1c) are good candidates.
Using PROCINFO in gnu-awk you can use this solution to sort on multi-character delimiter:
awk -F '\\|\\|' '{a[$2,$17] = $0} END {
PROCINFO["sorted_in"]="#ind_str_asc"; for (i in a) print a[i]}' file.csv
You could try following awk code. Written as per your shown attempts only. Set OFS as |(this is putting | as output field separator in case you want it ,comma etc then change OFS value accordingly in program) and print 17th field also as per your requirement in awk program. In sort use 1st and 2nd fields to sort it(because now 4th and 17th fields have become 1st and 2nd fields respectively for sort).
awk -F'\\|\\|' -v OFS='\\|' '{print $4,$17}' abc.csv | sort -t'|' -k1.1 -k2.1 > output.csv
The sort command works on physical lines, which may or may not be acceptable. CSV files can contain quoted fields which contain newlines, which will throw off sort (and most other Unix line-oriented utilities; it's hard to write a correct Awk script for this scenario, too).
If you need to be able to manipulate arbitrary CSV files, probably look to a dedicated utility, or use a scripting language with proper CSV support. For example, assume you have a file like this:
Title,Number,Arbitrary text
"He said, ""Hello""",2,"There can be
newlines and
stuff"
No problem,1,Simple undramatic single-line CSV
In case it's not obvious, CSV is fundamentally just a text file, with some restrictions on how it can be formatted. To be valid CSV, every record should be comma-separated; any literal commas or newlines in the data needs to be quoted, and any literal quotes need to be doubled. There are many variations; different tools accept slightly different dialects. One common variation is TSV which uses tabs instead of commas as delimiters.
Here is a simple Python script which sorts the above file on the second field.
import csv
import sys
with open("test.csv", "r") as csvfile:
csvdata = csv.reader(csvfile)
lines = [line for line in csvdata]
titles = lines.pop(0) # comment out if you don't have a header
writer = csv.writer(sys.stdout)
writer.writerow(titles) # comment out if you don't have a header
writer.writerows(sorted(lines, key=lambda x: x[1]))
Using sys.stdout for output is slightly unconventional; obviously, adapt to suit your needs. The Python csv library documentation is obviously not designed primarily to be friendly for beginners, but it should not be impossible to figure out, and it's not hard to find examples of working code.
In Python, sorted() returns a copy of a list in sorted order. There is also sort() which sorts a list in-place. Both functions accept an optional keyword parameter to specify a custom sort order. To sort on the 4th and 17th fields, use
sorted(lines, key=lambda x: (x[3], x[16]))
(Python's indexing is zero-based, so [3] is the fourth element.)
To use | as a delimiter, specify delimiter='|' in the csv.reader() and csv.writer() calls. Unfortunately, Python doesn't easily let you use a multi-character delimiter, so you might have to preprocess the data to switch to a single-character delimiter which does not occur in the data, or properly quote the fields which contain the character you selected as your delimiter.
I have a huge table I want to extract information from. Firstly, I want to extract a certain line based on a pattern -> I've done that successfully with grep. However this line has loads of columns and I'm interested only in a couple of them that have a certain pattern in them (partial match - beginning of the string). Is it possible to extract only the columns and the number of the column (the nth column) for some partial matches? Hope I was clear enough.
Languages: Preferably in bash but I can also work in R, alternatively I'm open to suggestions if you think another language can be more helpful.
Thanks!
Awk is perfect for stuff like this. To help you write a script I think we need more details. But I'm guessing you'll want to use the print feature of awk. To print out the nth column of a file "your_file" do:
awk '{print $n}' your_file
In solving your problem you may also want to loop over all N columns which you can do via:
for i in {1..N} ;
do
awk -v col=${i} '{print $col}' your_file ;
done
I'm searching through text files using grep and sed commands and I also want the file names displayed before my results. However, I'm trying to remove part of the file name when it is displayed.
The file names are formatted like this: aja_EPL_1999_03_01.txt
I want to have only the date without the beginning letters and without the .txt extension.
I've been searching for an answer and it seems like it's possible to do that with a sed or a grep command by using something like this to look forward and back and extract between _ and .txt:
(?<=_)\d+(?=\.)
But I must be doing something wrong, because it hasn't worked for me and I possibly have to add something as well, so that it doesn't extract only the first number, but the whole date. Thanks in advance.
Edit: Adding also the working command I've used just in case. I imagine whatever command is needed would have to go at the beginning?
sed '/^$/d' *.txt | grep -P '(^([A-ZÖÄÜÕŠŽ].*)?[Pp][Aa][Ll]{2}.*[^\.]$)' *.txt --colour -A 1
The results look like this:
aja_EPL_1999_03_02.txt:PALLILENNUD : korraga üritavad ümbermaailmalendu kaks meeskonda
A desired output would be this:
1999_03_02:PALLILENNUD : korraga üritavad ümbermaailmalendu kaks meeskonda
First off, you might want to think about your regular expression. While the one you have you say works, I wonder if it could be simplified. You told us:
(^([A-ZÖÄÜÕŠŽ].*)?[Pp][Aa][Ll]{2}.*[^\.]$)
It looks to me as if this is intended to match lines that start with a case insensitive "PALL", possibly preceded by any number of other characters that start with a capital letter, and that lines must not end in a backslash or a dot. So valid lines might be any of:
PALLILENNUD : korraga üritavad etc etc
Õlu on kena. Do I have appalling speling?
Peeter Pall is a limnologist at EMU!
If you'd care to narrow down this description a little and perhaps provide some examples of lines that should be matched or skipped, we may be able to do better. For instance, your outer parentheses are probably unnecessary.
Now, let's clarify what your pipe isn't doing.
sed '/^$/d' *.txt
This reads all your .txt files as an input stream, deletes any empty lines, and prints the output to stdout.
grep -P 'regex' *.txt --otheroptions
This reads all your .txt files, and prints any lines that match regex. It does not read stdin.
So .. in the command line you're using right now, your sed command is utterly ignored, as sed's output is not being read by grep. You COULD instruct grep to read from both files and stdin:
$ echo "hello" > x.txt
$ echo "world" | grep "o" x.txt -
x.txt:hello
(standard input):world
But that's not what you're doing.
By default, when grep reads from multiple files, it will precede each match with the name of the file from whence that match originated. That's also what you're seeing in my example above -- two inputs, one x.txt and the other - a.k.a. stdin, separated by a colon from the match they supplied.
While grep does include the most minuscule capability for filtering (with -o, or GNU grep's \K with optional Perl compatible RE), it does NOT provide you with any options for formatting the filename. Since you can'd do anything with the output of grep, you're limited to either parsing the output you've got, or using some other tool.
Parsing is easy, if your filenames are predictably structured as they seem to be from the two examples you've provided.
For this, we can ignore that these lines contain a file and data. For the purpose of the filter, they are a stream which follows a pattern. It looks like you want to strip off all characters from the beginning of each line up to and not including the first digit. You can do this by piping through sed:
sed 's/^[^0-9]*//'
Or you can achieve the same effect by using grep's minimal filtering to return every match starting from the first digit:
grep -o '[0-9].*'
If this kind of pipe-fitting is not to your liking, you may want to replace your entire grep with something in awk that combines functionality:
$ awk '
/[\.]$/ {next} # skip lines ending in backslash or dot
/^([A-ZÖÄÜÕŠŽ].*)?PALL/ { # lines to match
f=FILENAME
sub(/^[^0-9]*/,"",f) # strip unwanted part of filename, like sed
printf "%s:%s\n", f, $0
getline # simulate the "-A 1" from grep
printf "%s:%s\n", f, $0
}' *.txt
Note that I haven't tested this, because I don't have your data to work with.
Also, awk doesn't include any of the fancy terminal-dependent colourization that GNU grep provides through the --colour option.
I need to find a duplicate entry in 2 different columns and keep only one of the duplicate and all unique entries. For me if A123 is in the first column and it show up later in the second column it's a duplicate. I also know for sure that A123 will always be paired to B123 by either being A123,B123 or B123,A123. I only need to keep one and it doesn't matter which one it is.
Ex: My input file would contain:
A123,B123
A234,B234
C123,D123
B123,A123
B234,A234
I'd like the output to be:
A123,B123
A234,B234
C123,D123
The best I can do is to extract the unique entries with :
awk -F',' 'NR==FNR{x[$1]++;next}; !x[$2]' file1 file1
or get only the duplicates with
awk -F',' 'NR==FNR{x[$1]++;next}; x[$2]' file1 file1
Any help would be greatly appreciated.
This can be shorter!
First print if the element is not yet present in the array. Then add the first field to the array. Only one run over the inputfile is necessary:
awk -F, '!x[$2];{x[$1]++}' file1
This awk one-liner works for your example:
awk -F, '!($2 in a){a[$1]=$0}END{for(x in a)print a[x]}' file
The conventional, idiomatic awk solution:
$ awk -F, '!seen[$1>$2 ? $1 : $2]++' file
A123,B123
A234,B234
C123,D123
By convention we always use seen (rather than x or anything else) as the array name when it represents a set where you want to check if it's index has been seen before, and using a ternary expression to produce the largest of the possible key values as the index ensures the order they appear in the input doesn't matter.
The above doesn't care about your unique situation where every $2 is paired to a specific $1 - it simply prints unique individual occurrences across a pair of fields. If you wanted it to work on the pair of fields combined (and assuming you have more fields so just using $0 as the index wouldn't work) that'd be:
awk -F, '!seen[$1>$2 ? $1 FS $2 : $2 FS $1]++' file
I'm facing an issue where I'm getting some special characters in my file at the beggining; a snap of the same below:
^#<9b>200931350515,test1,910,420032400825443
^#<9a>200931350515,test1,910,420032400825443
^#<9d>200931746996,test2,910,420031390086807
I'm using the following command to remove anything other than numbers in first column:
sed 's/^[^0-9]*//g' file.dat
No success on that. The file is created btw during a fastexport from Teradata, the process adds some special characters by itself during extract.
Any idea on the command?
If you want to remove any non-ASCII characters anywhere in a line, you can use tr.
tr -d '\000\200-\377' <file >file.new
Using perl
perl -lne 'print /\d+,.*/g'
200931350515,test1,910,420032400825443
200931350515,test1,910,420032400825443
200931746996,test2,910,420031390086807
matches only digits up to the first comma and then everything else.
sed is to big gun for such a small problem,
use cut to remove the beginning of each line:
cut -b 2- file.dat
Where 2- is the range of bytes you want to retain, I'm not sure how many such strange characters you have there, so I would experiment with 1-, 2-, 3-, 4-, 5-, etc.
It looks like the number of characters that should be removed is constant across all line. To remove a fixed number of characters from the beginning of each line, you could simply do
$ sed 's/^.....//' input >output
Adjust the number of dots to fit your need.