Implement the dog bash utility

Question

dog is a command-line utility that takes in an arbitrary number of arguments, the first of which is the text to be written and the others are arbitrarily many files.

The dog utility will split the text in equal portions over these files. If there is a remainder n, the first n files get an additional byte

dog is the opposite of cat, as such, forall x, the following should hold.

$> dog x a.txt b.txt ...
$> cat a.txt b.txt ...
x$>

Where ... indicates arbitrarily many files.

An example (12 bytes, 3 files, can be split evenly):

$> ./dog.py "Dogs vs Cats" a.txt b.txt c.txt
$> cat a.txt
Dogs$> cat b.txt
 vs $> cat c.txt
Cats$> cat a.txt b.txt c.txt
Dogs vs Cats$> 

An example with remainder (13 bytes, 5 files, remainder 3):

9$>./dog.py "0123456789abc" a.txt b.txt c.txt d.txt e.txt
$> cat a.txt
012$> cat b.txt
345$> cat c.txt
678$> cat d.txt
9a$> cat e.txt
bc$> cat a.txt b.txt c.txt d.txt e.txt
0123456789abc$>

Answer 1

Pyth - 12 bytes

.wMC,cl.zz.z

Uses builtin split function and then uses splat-map on the write function. Doesn't work online.

Answer 2

Python - 181 bytes

import sys
a=sys.argv
l=len
d=a[2:]
s=a[1]
n,r=divmod(l(s),l(d))
p=0
for i in range(l(d)):
    with open(d[i],'w') as f:
        o=n+int(i<=n)
        f.write(s[p:p+o])
        p+=o

Answer 3

PHP, 107 bytes

The golfed code:

for($i=1;++$i<$argc;fputs(fopen($argv[$i],w),substr($s=$argv[1],($i-2)*$l=ceil(strlen($s)/($argc-2)),$l)));

The detailed code:

$len = ceil(strlen($argv[1])/($argc - 2));
for ($i = 2; $i < $argc; $i ++) {
    $fh = fopen($argv[$i], 'w');
    fputs($fh, substr($argv[1], ($i - 2) * $len, $len));
    fclose($fh);          // omitted in the golfed version
}

Answer 4

Pure bash: 97

s=$1;shift;for((l=${#s}/$#,m=${#s}-l*$#,i=1;i<=$#;p+=q,i++)){
printf "${s:p:q=i>m?l:l+1}">${!i};}

As a function: (p= is only required for second run)

dog() { p=
    s=$1;shift;for((l=${#s}/$#,m=${#s}-l*$#,i=1;i<=$#;p+=q,i++)){
    printf "${s:p:q=i>m?l:l+1}">${!i};}
}

Tests

$> rm *
$> dog "Dogs vs Cats" a.txt b.txt c.txt
$> ls -l
total 12
-rw-r--r-- 1 user user 4 May 13 22:09 a.txt
-rw-r--r-- 1 user user 4 May 13 22:09 b.txt
-rw-r--r-- 1 user user 4 May 13 22:09 c.txt
$> cat {a,b,c}.txt;echo
Dogs vs Cats
$> 

All files is 4 byte len and concatenated in right order, contain "Dogs vs Cats".

$> rm *
$> dog "$(printf "%s" {0..9} {a..c})" {a..e}.txt 
$> ls -l
total 20
-rw-r--r-- 1 user user 3 May 13 22:09 a.txt
-rw-r--r-- 1 user user 3 May 13 22:09 b.txt
-rw-r--r-- 1 user user 3 May 13 22:09 c.txt
-rw-r--r-- 1 user user 2 May 13 22:09 d.txt
-rw-r--r-- 1 user user 2 May 13 22:09 e.txt
$> cat *;echo
0123456789abc
$> 

Firsts files is 3 byte len and last only 2, concatenated by alphabetic order, contain "0123456789abc".

Explanation (ungolfing):

If you hit: declare -f dog, bash will answer:

$> declare -f dog
dog () 
{ 
    p=;
    s=$1;
    shift;
    for ((l=${#s}/$#,m=${#s}-l*$#,i=1; i<=$#; p+=q,i++))
    do
        printf "${s:p:q=i>m?l:l+1}" > ${!i};
    done
}

This could be written:

dog2 () 
{ 
    position=0;
    string=$1;
    shift;
    partLen=$((${#string}/$#));
    oneMore=$((${#string}-partLen*$#));
    for ((i=1; i<=$#; i++))
    do
        if ((i<=oneMore)); then
            partQuant=$((partLen+1));
        else
            partQuant=$partLen;
        fi;
        printf "${string:position:partQuant}" > ${!i};
        ((position+=partQuant));
    done
}

Answer 5

Ruby, 93 87 bytes

Full program using command line arguments.

If I could use s.slice! to mutate the string, I'd do that instead of needing to use s[c..-1], but Ruby doesn't let you mutate the strings from argv without duplicating them first

s,*t=$*
d,r=s.size.divmod t.size
t.map{|e|open(e,?w)<<s[0,c=(0>r-=1)?d:d+1];s=s[c..-1]}