I am trying to find the reason of this command and as I know very basic I found that
last | cut -d" " -f 1 | sort | uniq -c | sort
last = Last searches back through the file /var/log/wtmp (or the file designated by the -f flag) and displays a list of all users logged in (and out) since that file was created.
cut is to show the desired column.
The option -d specifies what is the field delimiter that is used in the input file.
-f specifies which field you want to extract
1 is the out put I think which I am not sure
and the it is sorting and then it is
Uniq command is helpful to remove or detect duplicate entries in a file. This tutorial explains few most frequently used uniq command line options that you might find helpful.
If anyone can explain this command and also explain why there is two sorts I will appreciate it.
You are right on your explanation of cut: cut -d" " -f1 (no need of space after f) gets the first field of a stream based on delimiter " " (space).
Then why sort | uniq -c | sort?
From man uniq:
Note: 'uniq' does not detect repeated lines unless they are adjacent.
You may want to sort the input first, or use 'sort -u' without 'uniq'.
Also, comparisons honor the rules specified by 'LC_COLLATE'.
That's why you need to sort the lines before piping to uniq. Finally, as uniq output is not sorted, you need to sort again to see the most repeated items first.
See an example of sort and uniq -c for a given file with repeated items:
$ seq 5 >>a
$ seq 5 >>a
$ cat a
1
2
3
4
5
1
2
3
4
5
$ sort a | uniq -c | sort <--- no repeated matches
2 1
2 2
2 3
2 4
2 5
$ uniq -c a | sort <---- repeated matches
1 1
1 1
1 2
1 2
1 3
1 3
1 4
1 4
1 5
1 5
Note you can do the sort | uniq -c all together with this awk:
last | awk '{a[$1]++} END{for (i in a) print i, a[i]}'
This will store in the a[] array the values of the first column and increase the counter whenever it finds more. In the END{} blocks it prints the results, unsorted, so you could pipe again to sort.
uniq -c is being used to create a frequency histogram. The reason for the second sort is that you are then sorting your histogram by frequency order.
The reason for the first sort is that uniq is only comparing each line to its previous when deciding whether the line is unique or not.
Related
I have a text file that contains names like the following:
cup-1.5.1-1_d03.rpm
cup-1.5-2_d03.rpm
cup-1.5.1-2_d03.rpm
cup-1.5-3_d03.rpm
I know that cup-1.5.1-2_d03.rpm should be the latest version. Is there a way to sort it properly so that the output would look like,
cup-1.5-2_d03.rpm
cup-1.5-3_d03.rpm
cup-1.5.1-1_d03.rpm
cup-1.5.1-2_d03.rpm
I tried
$ grep -o -P '(?<=cup-)[0-9]+.[0-9]+.*[0-9]+(?=.*.rpm)' a.txt | tr '.' ' ' | tr '-' ' ' | sort -k4
1 5 2_d03
1 5 3_d03
1 5 1 1_d03
1 5 1 2_d03
but not sure how can I achieve it for the entire string. I have yet another file that has a little different versioning, where the field would be -k5.
$ cat b.txt
dup-1.1.1-3_d03.rpm
dup-1.1.1.1-1_d03.rpm
dup-1.1.1-1_d03.rpm
Here, I would expect an output:
dup-1.1.1-1_d03.rpm
dup-1.1.1-3_d03.rpm
dup-1.1.1.1-1_d03.rpm
Is there a way to sort these two files programmatically without relying on rpm utility if at all possible ?
Use sort -V (version):
sort -V file
cup-1.5-2_d03.rpm
cup-1.5-3_d03.rpm
cup-1.5.1-1_d03.rpm
cup-1.5.1-2_d03.rpm
I have a file that has the following user names in random places in the file:
albert#ghhdh
albert#jdfjgjjg
john#jfkfeie
mike#fjfkjf
bill#fjfj
bill#fkfkfk
Usernames are the names to the left of the # symbol.
I want to use unix commands to grep the file for usernames, then make a count of unique usernames.
Therefore using the example above, the output should state that there are 4 unique users (I just need the count as the output, no words)
Can someone help me determine the correct count?
You could extract the words before #, sort them and count them :
cat test.txt | cut -d '#' -f 1 | sort | uniq -c
With test.txt :
albert#ghhdh
john#jfkfeie
bill#fjfj
mike#fjfkjf
bill#fkfkfk
albert#jdfjgjjg
It outputs :
2 albert
2 bill
1 john
1 mike
Note that the duplicate usernames don't have to be grouped in the input list.
If you're just interested in the count of uniq users :
cat test.txt | cut -d '#' -f 1 | sort -u | wc -l
# => 4
Or shorter :
cut -d '#' -f 1 test.txt | sort -u | wc -l
Here is the solution that finds the usernames anywhere on the line (not just at the beginning), even if there are multiple usernames on a single line, and finds their unique count:
grep -oE '\b[[:alpha:]_][[:alnum:]_.]*#' file | cut -f1 -d# | sort -u | wc -l
-o only fetches the matched portion
-E processes extended regex
\b[[:alpha:]_][[:alnum:]]*# matches usernames (a string following a word boundary \b that starts with an alpha or underscore followed by zero or more alphanumeric and other permitted characters, ending with a #
cut -f1 -d# extracts the username portion which is then sorted and counted for unique names
Faster with one awk command, if awk is allowed:
awk -F"#" '!seen[$1]++{c++}END{print "Unique users =" c}'
Small Explanation:
using # as delimiter (-F) you look for field 1 = $1 for awk.
For every field 1 that is not seen again we increase a counter c.
In the same time we increase the particular field1 so if found again the test "not seen" will not be valid.
At the end we just print the counter of unique "seen".
As a plus, this solution does not require pre-sorting. Duplicates would be found even if file is not sorted.
Sample file
aa\bb\cc\dd\ee\ff\gg\hh\ii\jj
aa\bb\cc\dd\ee\ll\gg\hh\ii\jj
aa\bb\cc\dd\ee\ff\gg\hh\ii\jj
I want to skip 6th field 'ff' when comparing for an unique line, also I want the count of # of duplicate lines in front.
I tried this, without any luck:
sort -t'\' -k1,5 -k7 --unique xslin1 > xslout
Expected output
3 aa\bb\cc\dd\ee\*\gg\hh\ii\jj
$ awk -F'\' -v OFS='\' '{$6="*"} 1' xslin1 | sort | uniq -c
3 aa\bb\cc\dd\ee\*\gg\hh\ii\jj
Discussion
With --unique, sort outputs only unique lines but it does not count them. One needs uniq -c for that. Further, sort outputs all unique lines, not just those that sort to the same value.
The above solution does the simple approach of assigning the sixth field to *, as you wanted in the output, and then uses the standard pipeline, sort | uniq -c, to produce the count of unique lines.
You can do this in one awk:
awk 'BEGIN{FS=OFS="\\"} {$6="*"} uniq[$0]++{}
END {for (i in uniq) print uniq[i] "\t" i}' file
3 aa\bb\cc\dd\ee\*\gg\hh\ii\jj
I have this array:
array=(1 2 3 4 4 3 4 3)
I can get the largest number with:
echo "num: $(printf "%d\n" ${array[#]} | sort -nr | head -n 1)"
#outputs 4
But i want to get all 4's add sum them up, meaning I want it to output 12 (there are 3 occurrences of 4) instead. any ideas?
dc <<<"$(printf '%d\n' "${array[#]}" | sort -n | uniq -c | tail -n 1) * p"
sort to get max value at end
uniq -c to get only unique values, with a count of how many times they appear
tail to get only the last line (with the max value and its count)
dc to multiply the value by the count
I picked dc for the multiplication step because it's RPN, so you don't have to split up the uniq -c output and insert anything in the middle of it - just add stuff to the end.
Using awk:
$ printf "%d\n" "${array[#]}" | sort -nr | awk 'NR>1 && p!=$0{print x;exit;}{x+=$0;p=$0;}'
12
Using sort, the numbers are sorted(-n) in reverse(-r) order, and the awk keeps summing the numbers till it finds a number which is different from the previous one.
You can do this with awk:
awk -v RS=" " '{sum[$0]+=$0; if($0>max) max=$0} END{print sum[max]}' <<<"${array[#]}"
Setting RS (record separator) to space allows you to read your array entries as separate records.
sum[$0]+=$0; means sum is a map of cumulative sums for each input value; if($0>max) max=$0 calculates the max number seen so far; END{print sum[max]} prints the sum for the larges number seen at the end.
<<<"${array[#]}" is a here-document that allows you to feed a string (in this case all elements of the array) as stdin into awk.
This way there is no piping or looping involved - a single command does all the work.
Using only bash:
echo $((${array// /+}))
Replace all spaces with plus, and evaluate using double-parentheses expression.
I have a text file with a large amount of data which is tab delimited. I want to have a look at the data such that I can see the unique values in a column. For example,
Red Ball 1 Sold
Blue Bat 5 OnSale
...............
So, its like the first column has colors, so I want to know how many different unique values are there in that column and I want to be able to do that for each column.
I need to do this in a Linux command line, so probably using some bash script, sed, awk or something.
What if I wanted a count of these unique values as well?
Update: I guess I didn't put the second part clearly enough. What I wanted to do is to have a count of "each" of these unique values not know how many unique values are there. For instance, in the first column I want to know how many Red, Blue, Green etc coloured objects are there.
You can make use of cut, sort and uniq commands as follows:
cat input_file | cut -f 1 | sort | uniq
gets unique values in field 1, replacing 1 by 2 will give you unique values in field 2.
Avoiding UUOC :)
cut -f 1 input_file | sort | uniq
EDIT:
To count the number of unique occurences you can make use of wc command in the chain as:
cut -f 1 input_file | sort | uniq | wc -l
awk -F '\t' '{ a[$1]++ } END { for (n in a) print n, a[n] } ' test.csv
You can use awk, sort & uniq to do this, for example to list all the unique values in the first column
awk < test.txt '{print $1}' | sort | uniq
As posted elsewhere, if you want to count the number of instances of something you can pipe the unique list into wc -l
Assuming the data file is actually Tab separated, not space aligned:
<test.tsv awk '{print $4}' | sort | uniq
Where $4 will be:
$1 - Red
$2 - Ball
$3 - 1
$4 - Sold
# COLUMN is integer column number
# INPUT_FILE is input file name
cut -f ${COLUMN} < ${INPUT_FILE} | sort -u | wc -l
Here is a bash script that fully answers the (revised) original question. That is, given any .tsv file, it provides the synopsis for each of the columns in turn. Apart from bash itself, it only uses standard *ix/Mac tools: sed tr wc cut sort uniq.
#!/bin/bash
# Syntax: $0 filename
# The input is assumed to be a .tsv file
FILE="$1"
cols=$(sed -n 1p $FILE | tr -cd '\t' | wc -c)
cols=$((cols + 2 ))
i=0
for ((i=1; i < $cols; i++))
do
echo Column $i ::
cut -f $i < "$FILE" | sort | uniq -c
echo
done
This script outputs the number of unique values in each column of a given file. It assumes that first line of given file is header line. There is no need for defining number of fields. Simply save the script in a bash file (.sh) and provide the tab delimited file as a parameter to this script.
Code
#!/bin/bash
awk '
(NR==1){
for(fi=1; fi<=NF; fi++)
fname[fi]=$fi;
}
(NR!=1){
for(fi=1; fi<=NF; fi++)
arr[fname[fi]][$fi]++;
}
END{
for(fi=1; fi<=NF; fi++){
out=fname[fi];
for (item in arr[fname[fi]])
out=out"\t"item"_"arr[fname[fi]][item];
print(out);
}
}
' $1
Execution Example:
bash> ./script.sh <path to tab-delimited file>
Output Example
isRef A_15 C_42 G_24 T_18
isCar YEA_10 NO_40 NA_50
isTv FALSE_33 TRUE_66