I'm trying to perform some floating point arithmetic in bash and I get these errors in terminal:
$
(standard_in) 2: parse error
(standard_in) 2: parse error
(standard_in) 1: parse error
The code that is throwing these errors is:
qlen=$(awk '{print $2 ; exit}' $filepath/result)
slen=$(awk '{print $3 ; exit}' $filepath/result)
len=$(awk 'BEGIN{max = 0} {if (($4) > max) max = ($4)} END {print max}' $filepath/result)
qcov=$(echo $len / $qlen | bc -l) #parse error 2
scov=$(echo $len / $slen | bc -l) #parse error 2
if (( $(echo "$qcov >= .7" | bc -l) )) && (( $(echo "$scov >= .7" | bc -l) )) #parse error 1???
then
score=$(awk '{ total += $1; count++ } END { if (count > 0) {printf "%f", total/count} }' $filepath/result) #parse error 1???
else
score=0
fi
I find the max number in column $4 and divide it by the numbers in column $2 and $3. I want the floating point result, not integer arithmetic. I save this floating point number into qcov and scov and use a conditional operator within the if-statement. I think I've narrowed down the exact lines where these parse errors are occurring which are commented above. They all stem from the bc command.
The input file $filepath/result looks like this:
34.234 234 756 34 3 34
76.542 234 756 7 64 76
63.357 234 756 97 5 35
You can see this file as a space delimited table. Column $2 and $3 are always the same number, so, the awk statement assigning qlen and slen should behave as expected with the exit statement.
My best guess is that there is some problem when the if-statement evaluates to true, but I don't quite understand what is going wrong beyond that.
Thanks in advance.
EDIT:
Thanks to everyone who helped, I figured out why I got these errors. The file result is being created every time I call this set of code. There were cases where the program creating it would not print anything, resulting in EOF (?) at the beginning and causing the parse errors I got. I]m fairly certain that is why I got parse errors.
not sure why you do so many shell operations when you have the full power of awk.
find the max of column 4 and divide by columns 2 and 3.
$ awk 'NR==FNR{if(max<$4) max=$4; next} {print max/$2, max/$3}' file{,}
0.41453 0.128307
0.41453 0.128307
0.41453 0.128307
I didn't understand what you do next, but you should be able to add to this script easily as well.
#Justin: Your file result has several lines. Hence, qlen and slen is a string with several numbers embedded. You can see this problem immediately, when you run your script with -x.
I have a text file (bigfile.txt) with thousands of rows. I want to make a smaller text file with 1 % of the rows which are randomly chosen. I tried the following
output=$(wc -l bigfile.txt)
ds1=$(0.01*output)
sort -r bigfile.txt|shuf|head -n ds1
It give the following error:
head: invalid number of lines: ‘ds1’
I don't know what is wrong.
Even after you fix your issues with your bash script, it cannot do floating point arithmetic. You need external tools like Awk which I would use as
randomCount=$(awk 'END{print int((NR==0)?0:(NR/100))}' bigfile.txt)
(( randomCount )) && sort -r file | shuf | head -n "$randomCount"
E.g. Writing a file with with 221 lines using the below loop and trying to get random lines,
tmpfile=$(mktemp /tmp/abc-script.XXXXXX)
for i in {1..221}; do echo $i; done >> "$tmpfile"
randomCount=$(awk 'END{print int((NR==0)?0:(NR/100))}' "$tmpfile")
If I print the count, it would return me a integer number 2 and using that on the next command,
sort -r "$tmpfile" | shuf | head -n "$randomCount"
86
126
Roll a die (with rand()) for each line of the file and get a number between 0 and 1. Print the line if the die shows less than 0.01:
awk 'rand()<0.01' bigFile
Quick test - generate 100,000,000 lines and count how many get through:
seq 1 100000000 | awk 'rand()<0.01' | wc -l
999308
Pretty close to 1%.
If you want the order random as well as the selection, you can pass this through shuf afterwards:
seq 1 100000000 | awk 'rand()<0.01' | shuf
On the subject of efficiency which came up in the comments, this solution takes 24s on my iMac with 100,000,000 lines:
time { seq 1 100000000 | awk 'rand()<0.01' > /dev/null; }
real 0m23.738s
user 0m31.787s
sys 0m0.490s
The only other solution that works here, heavily based on OP's original code, takes 13 minutes 19s.
I have a question. I have a file with coordinates (TAB separated)
2 10
35 50
90 200
400 10000
...
I would like to substract the first column of the second line from the second column of the fist line , i.e. calculate the distance, i.e. I would like a file with
25
40
200
...
How could I do that using awk???
Thank you very much in advance
here is an awk one-liner may help you:
kent$ awk 'a{print $1-a}{a=$2}' file
25
40
200
Here's a pure bash solution:
{
read _ ps
while read f s; do
echo $((f-ps))
((ps=s))
done
} < input_file
This only works if you have (small) integers, as it uses bash's arithmetic. If you want to deal with arbitrary sized integers or floats, you can use bc (with only one fork):
{
read _ ps
while read f s; do
printf '%s-%s\n' "$f" "$ps"
ps=$s
done
} < input_file | bc
Now I leave the others give an awk answer!
Alright, since nobody wants to upvote my answer, here's a really funny solution that uses bash and bc:
a=( $(<input_file) )
printf -- '-(%s)+(%s);\n' "${a[#]:1:${#a[#]}-2}" | bc
or the same with dc (shorter but doesn't work with negative numbers):
a=( $(<input_file) )
printf '%s %sr-pc' "${a[#]:1:${#a[#]}-2}" | dc
using sed and ksh for evaluation
sed -n "
1x
1!H
$ !b
x
s/^ *[0-9]\{1,\} \(.*\) [0-9]\{1,\} *\n* *$/\1 /
s/\([0-9]\{1,\}\)\(\n\)\([0-9]\{1,\}\) /echo \$((\3 - \1))\2/g
s/\n *$//
w /tmp/Evaluate.me
"
. /tmp/Evaluate.me
rm /tmp/Evaluate.me
What's an easy way to read random line from a file in a shell script?
You can use shuf:
shuf -n 1 $FILE
There is also a utility called rl. In Debian it's in the randomize-lines package that does exactly what you want, though not available in all distros. On its home page it actually recommends the use of shuf instead (which didn't exist when it was created, I believe). shuf is part of the GNU coreutils, rl is not.
rl -c 1 $FILE
Another alternative:
head -$((${RANDOM} % `wc -l < file` + 1)) file | tail -1
sort --random-sort $FILE | head -n 1
(I like the shuf approach above even better though - I didn't even know that existed and I would have never found that tool on my own)
This is simple.
cat file.txt | shuf -n 1
Granted this is just a tad slower than the "shuf -n 1 file.txt" on its own.
perlfaq5: How do I select a random line from a file? Here's a reservoir-sampling algorithm from the Camel Book:
perl -e 'srand; rand($.) < 1 && ($line = $_) while <>; print $line;' file
This has a significant advantage in space over reading the whole file in. You can find a proof of this method in The Art of Computer Programming, Volume 2, Section 3.4.2, by Donald E. Knuth.
using a bash script:
#!/bin/bash
# replace with file to read
FILE=tmp.txt
# count number of lines
NUM=$(wc - l < ${FILE})
# generate random number in range 0-NUM
let X=${RANDOM} % ${NUM} + 1
# extract X-th line
sed -n ${X}p ${FILE}
Single bash line:
sed -n $((1+$RANDOM%`wc -l test.txt | cut -f 1 -d ' '`))p test.txt
Slight problem: duplicate filename.
Here's a simple Python script that will do the job:
import random, sys
lines = open(sys.argv[1]).readlines()
print(lines[random.randrange(len(lines))])
Usage:
python randline.py file_to_get_random_line_from
Another way using 'awk'
awk NR==$((${RANDOM} % `wc -l < file.name` + 1)) file.name
A solution that also works on MacOSX, and should also works on Linux(?):
N=5
awk 'NR==FNR {lineN[$1]; next}(FNR in lineN)' <(jot -r $N 1 $(wc -l < $file)) $file
Where:
N is the number of random lines you want
NR==FNR {lineN[$1]; next}(FNR in lineN) file1 file2
--> save line numbers written in file1 and then print corresponding line in file2
jot -r $N 1 $(wc -l < $file) --> draw N numbers randomly (-r) in range (1, number_of_line_in_file) with jot. The process substitution <() will make it look like a file for the interpreter, so file1 in previous example.
#!/bin/bash
IFS=$'\n' wordsArray=($(<$1))
numWords=${#wordsArray[#]}
sizeOfNumWords=${#numWords}
while [ True ]
do
for ((i=0; i<$sizeOfNumWords; i++))
do
let ranNumArray[$i]=$(( ( $RANDOM % 10 ) + 1 ))-1
ranNumStr="$ranNumStr${ranNumArray[$i]}"
done
if [ $ranNumStr -le $numWords ]
then
break
fi
ranNumStr=""
done
noLeadZeroStr=$((10#$ranNumStr))
echo ${wordsArray[$noLeadZeroStr]}
Here is what I discovery since my Mac OS doesn't use all the easy answers. I used the jot command to generate a number since the $RANDOM variable solutions seems not to be very random in my test. When testing my solution I had a wide variance in the solutions provided in the output.
RANDOM1=`jot -r 1 1 235886`
#range of jot ( 1 235886 ) found from earlier wc -w /usr/share/dict/web2
echo $RANDOM1
head -n $RANDOM1 /usr/share/dict/web2 | tail -n 1
The echo of the variable is to get a visual of the generated random number.
Using only vanilla sed and awk, and without using $RANDOM, a simple, space-efficient and reasonably fast "one-liner" for selecting a single line pseudo-randomly from a file named FILENAME is as follows:
sed -n $(awk 'END {srand(); r=rand()*NR; if (r<NR) {sub(/\..*/,"",r); r++;}; print r}' FILENAME)p FILENAME
(This works even if FILENAME is empty, in which case no line is emitted.)
One possible advantage of this approach is that it only calls rand() once.
As pointed out by #AdamKatz in the comments, another possibility would be to call rand() for each line:
awk 'rand() * NR < 1 { line = $0 } END { print line }' FILENAME
(A simple proof of correctness can be given based on induction.)
Caveat about rand()
"In most awk implementations, including gawk, rand() starts generating numbers from the same starting number, or seed, each time you run awk."
-- https://www.gnu.org/software/gawk/manual/html_node/Numeric-Functions.html
I am looking for a command that will accept (as input) multiple lines of text, each line containing a single integer, and output the sum of these integers.
As a bit of background, I have a log file which includes timing measurements. Through grepping for the relevant lines and a bit of sed reformatting I can list all of the timings in that file. I would like to work out the total. I can pipe this intermediate output to any command in order to do the final sum. I have always used expr in the past, but unless it runs in RPN mode I do not think it is going to cope with this (and even then it would be tricky).
How can I get the summation of integers?
Bit of awk should do it?
awk '{s+=$1} END {print s}' mydatafile
Note: some versions of awk have some odd behaviours if you are going to be adding anything exceeding 2^31 (2147483647). See comments for more background. One suggestion is to use printf rather than print:
awk '{s+=$1} END {printf "%.0f", s}' mydatafile
Paste typically merges lines of multiple files, but it can also be used to convert individual lines of a file into a single line. The delimiter flag allows you to pass a x+x type equation to bc.
paste -s -d+ infile | bc
Alternatively, when piping from stdin,
<commands> | paste -s -d+ - | bc
The one-liner version in Python:
$ python -c "import sys; print(sum(int(l) for l in sys.stdin))"
I would put a big WARNING on the commonly approved solution:
awk '{s+=$1} END {print s}' mydatafile # DO NOT USE THIS!!
that is because in this form awk uses a 32 bit signed integer representation: it will overflow for sums that exceed 2147483647 (i.e., 2^31).
A more general answer (for summing integers) would be:
awk '{s+=$1} END {printf "%.0f\n", s}' mydatafile # USE THIS INSTEAD
Plain bash:
$ cat numbers.txt
1
2
3
4
5
6
7
8
9
10
$ sum=0; while read num; do ((sum += num)); done < numbers.txt; echo $sum
55
With jq:
seq 10 | jq -s 'add' # 'add' is equivalent to 'reduce .[] as $item (0; . + $item)'
dc -f infile -e '[+z1<r]srz1<rp'
Note that negative numbers prefixed with minus sign should be translated for dc, since it uses _ prefix rather than - prefix for that. For example, via tr '-' '_' | dc -f- -e '...'.
Edit: Since this answer got so many votes "for obscurity", here is a detailed explanation:
The expression [+z1<r]srz1<rp does the following:
[ interpret everything to the next ] as a string
+ push two values off the stack, add them and push the result
z push the current stack depth
1 push one
<r pop two values and execute register r if the original top-of-stack (1)
is smaller
] end of the string, will push the whole thing to the stack
sr pop a value (the string above) and store it in register r
z push the current stack depth again
1 push 1
<r pop two values and execute register r if the original top-of-stack (1)
is smaller
p print the current top-of-stack
As pseudo-code:
Define "add_top_of_stack" as:
Remove the two top values off the stack and add the result back
If the stack has two or more values, run "add_top_of_stack" recursively
If the stack has two or more values, run "add_top_of_stack"
Print the result, now the only item left in the stack
To really understand the simplicity and power of dc, here is a working Python script that implements some of the commands from dc and executes a Python version of the above command:
### Implement some commands from dc
registers = {'r': None}
stack = []
def add():
stack.append(stack.pop() + stack.pop())
def z():
stack.append(len(stack))
def less(reg):
if stack.pop() < stack.pop():
registers[reg]()
def store(reg):
registers[reg] = stack.pop()
def p():
print stack[-1]
### Python version of the dc command above
# The equivalent to -f: read a file and push every line to the stack
import fileinput
for line in fileinput.input():
stack.append(int(line.strip()))
def cmd():
add()
z()
stack.append(1)
less('r')
stack.append(cmd)
store('r')
z()
stack.append(1)
less('r')
p()
Pure and short bash.
f=$(cat numbers.txt)
echo $(( ${f//$'\n'/+} ))
perl -lne '$x += $_; END { print $x; }' < infile.txt
My fifteen cents:
$ cat file.txt | xargs | sed -e 's/\ /+/g' | bc
Example:
$ cat text
1
2
3
3
4
5
6
78
9
0
1
2
3
4
576
7
4444
$ cat text | xargs | sed -e 's/\ /+/g' | bc
5148
I've done a quick benchmark on the existing answers which
use only standard tools (sorry for stuff like lua or rocket),
are real one-liners,
are capable of adding huge amounts of numbers (100 million), and
are fast (I ignored the ones which took longer than a minute).
I always added the numbers of 1 to 100 million which was doable on my machine in less than a minute for several solutions.
Here are the results:
Python
:; seq 100000000 | python -c 'import sys; print sum(map(int, sys.stdin))'
5000000050000000
# 30s
:; seq 100000000 | python -c 'import sys; print sum(int(s) for s in sys.stdin)'
5000000050000000
# 38s
:; seq 100000000 | python3 -c 'import sys; print(sum(int(s) for s in sys.stdin))'
5000000050000000
# 27s
:; seq 100000000 | python3 -c 'import sys; print(sum(map(int, sys.stdin)))'
5000000050000000
# 22s
:; seq 100000000 | pypy -c 'import sys; print(sum(map(int, sys.stdin)))'
5000000050000000
# 11s
:; seq 100000000 | pypy -c 'import sys; print(sum(int(s) for s in sys.stdin))'
5000000050000000
# 11s
Awk
:; seq 100000000 | awk '{s+=$1} END {print s}'
5000000050000000
# 22s
Paste & Bc
This ran out of memory on my machine. It worked for half the size of the input (50 million numbers):
:; seq 50000000 | paste -s -d+ - | bc
1250000025000000
# 17s
:; seq 50000001 100000000 | paste -s -d+ - | bc
3750000025000000
# 18s
So I guess it would have taken ~35s for the 100 million numbers.
Perl
:; seq 100000000 | perl -lne '$x += $_; END { print $x; }'
5000000050000000
# 15s
:; seq 100000000 | perl -e 'map {$x += $_} <> and print $x'
5000000050000000
# 48s
Ruby
:; seq 100000000 | ruby -e "puts ARGF.map(&:to_i).inject(&:+)"
5000000050000000
# 30s
C
Just for comparison's sake I compiled the C version and tested this also, just to have an idea how much slower the tool-based solutions are.
#include <stdio.h>
int main(int argc, char** argv) {
long sum = 0;
long i = 0;
while(scanf("%ld", &i) == 1) {
sum = sum + i;
}
printf("%ld\n", sum);
return 0;
}
:; seq 100000000 | ./a.out
5000000050000000
# 8s
Conclusion
C is of course fastest with 8s, but the Pypy solution only adds a very little overhead of about 30% to 11s. But, to be fair, Pypy isn't exactly standard. Most people only have CPython installed which is significantly slower (22s), exactly as fast as the popular Awk solution.
The fastest solution based on standard tools is Perl (15s).
Using the GNU datamash util:
seq 10 | datamash sum 1
Output:
55
If the input data is irregular, with spaces and tabs at odd places, this may confuse datamash, then either use the -W switch:
<commands...> | datamash -W sum 1
...or use tr to clean up the whitespace:
<commands...> | tr -d '[[:blank:]]' | datamash sum 1
If the input is large enough, the output will be in scientific notation.
seq 100000000 | datamash sum 1
Output:
5.00000005e+15
To convert that to decimal, use the the --format option:
seq 100000000 | datamash --format '%.0f' sum 1
Output:
5000000050000000
Plain bash one liner
$ cat > /tmp/test
1
2
3
4
5
^D
$ echo $(( $(cat /tmp/test | tr "\n" "+" ) 0 ))
BASH solution, if you want to make this a command (e.g. if you need to do this frequently):
addnums () {
local total=0
while read val; do
(( total += val ))
done
echo $total
}
Then usage:
addnums < /tmp/nums
You can using num-utils, although it may be overkill for what you need. This is a set of programs for manipulating numbers in the shell, and can do several nifty things, including of course, adding them up. It's a bit out of date, but they still work and can be useful if you need to do something more.
https://suso.suso.org/programs/num-utils/index.phtml
It's really simple to use:
$ seq 10 | numsum
55
But runs out of memory for large inputs.
$ seq 100000000 | numsum
Terminado (killed)
The following works in bash:
I=0
for N in `cat numbers.txt`
do
I=`expr $I + $N`
done
echo $I
I realize this is an old question, but I like this solution enough to share it.
% cat > numbers.txt
1
2
3
4
5
^D
% cat numbers.txt | perl -lpe '$c+=$_}{$_=$c'
15
If there is interest, I'll explain how it works.
Cannot avoid submitting this, it is the most generic approach to this Question, please check:
jot 1000000 | sed '2,$s/$/+/;$s/$/p/' | dc
It is to be found over here, I was the OP and the answer came from the audience:
Most elegant unix shell one-liner to sum list of numbers of arbitrary precision?
And here are its special advantages over awk, bc, perl, GNU's datamash and friends:
it uses standards utilities common in any unix environment
it does not depend on buffering and thus it does not choke with really long inputs.
it implies no particular precision limits -or integer size for that matter-, hello AWK friends!
no need for different code, if floating point numbers need to be added, instead.
it theoretically runs unhindered in the minimal of environments
sed 's/^/.+/' infile | bc | tail -1
Pure bash and in a one-liner :-)
$ cat numbers.txt
1
2
3
4
5
6
7
8
9
10
$ I=0; for N in $(cat numbers.txt); do I=$(($I + $N)); done; echo $I
55
Alternative pure Perl, fairly readable, no packages or options required:
perl -e "map {$x += $_} <> and print $x" < infile.txt
For Ruby Lovers
ruby -e "puts ARGF.map(&:to_i).inject(&:+)" numbers.txt
Here's a nice and clean Raku (formerly known as Perl 6) one-liner:
say [+] slurp.lines
We can use it like so:
% seq 10 | raku -e "say [+] slurp.lines"
55
It works like this:
slurp without any arguments reads from standard input by default; it returns a string. Calling the lines method on a string returns a list of lines of the string.
The brackets around + turn + into a reduction meta operator which reduces the list to a single value: the sum of the values in the list. say then prints it to standard output with a newline.
One thing to note is that we never explicitly convert the lines to numbers—Raku is smart enough to do that for us. However, this means our code breaks on input that definitely isn't a number:
% echo "1\n2\nnot a number" | raku -e "say [+] slurp.lines"
Cannot convert string to number: base-10 number must begin with valid digits or '.' in '⏏not a number' (indicated by ⏏)
in block <unit> at -e line 1
You can do it in python, if you feel comfortable:
Not tested, just typed:
out = open("filename").read();
lines = out.split('\n')
ints = map(int, lines)
s = sum(ints)
print s
Sebastian pointed out a one liner script:
cat filename | python -c"from fileinput import input; print sum(map(int, input()))"
The following should work (assuming your number is the second field on each line).
awk 'BEGIN {sum=0} \
{sum=sum + $2} \
END {print "tot:", sum}' Yourinputfile.txt
$ cat n
2
4
2
7
8
9
$ perl -MList::Util -le 'print List::Util::sum(<>)' < n
32
Or, you can type in the numbers on the command line:
$ perl -MList::Util -le 'print List::Util::sum(<>)'
1
3
5
^D
9
However, this one slurps the file so it is not a good idea to use on large files. See j_random_hacker's answer which avoids slurping.
One-liner in Racket:
racket -e '(define (g) (define i (read)) (if (eof-object? i) empty (cons i (g)))) (foldr + 0 (g))' < numlist.txt
C (not simplified)
seq 1 10 | tcc -run <(cat << EOF
#include <stdio.h>
int main(int argc, char** argv) {
int sum = 0;
int i = 0;
while(scanf("%d", &i) == 1) {
sum = sum + i;
}
printf("%d\n", sum);
return 0;
}
EOF)
My version:
seq -5 10 | xargs printf "- - %s" | xargs | bc
C++ (simplified):
echo {1..10} | scc 'WRL n+=$0; n'
SCC project - http://volnitsky.com/project/scc/
SCC is C++ snippets evaluator at shell prompt