I have an array from with numbers from 1 to 100:
array=$(seq 100)
My task is to exclude range from 60 to 80.
You can use parameter expansion with the offset/length specification.
#! /bin/bash
arr=({1..100})
exclude_from=60
exclude_to=80
echo "${arr[#]:0:exclude_from-1}" "${arr[#]:exclude_to}"
An arithmetic test condition
for n in {1..100}; do
(( 60 <= n && n <= 80 )) && continue
echo $n
done
However, to remove those elements from an array
ary=({1..100})
# note that number 1 is stored in _index_ 0
for ((n=60; n <= 80; n++)); do
unset "ary[$((n-1))]"
done
declare -p ary
outputs
declare -a ary=([0]="1" [1]="2" [2]="3" [3]="4" [4]="5" [5]="6" [6]="7" [7]="8" [8]="9" [9]="10" [10]="11" [11]="12" [12]="13" [13]="14" [14]="15" [15]="16" [16]="17" [17]="18" [18]="19" [19]="20" [20]="21" [21]="22" [22]="23" [23]="24" [24]="25" [25]="26" [26]="27" [27]="28" [28]="29" [29]="30" [30]="31" [31]="32" [32]="33" [33]="34" [34]="35" [35]="36" [36]="37" [37]="38" [38]="39" [39]="40" [40]="41" [41]="42" [42]="43" [43]="44" [44]="45" [45]="46" [46]="47" [47]="48" [48]="49" [49]="50" [50]="51" [51]="52" [52]="53" [53]="54" [54]="55" [55]="56" [56]="57" [57]="58" [58]="59" [80]="81" [81]="82" [82]="83" [83]="84" [84]="85" [85]="86" [86]="87" [87]="88" [88]="89" [89]="90" [90]="91" [91]="92" [92]="93" [93]="94" [94]="95" [95]="96" [96]="97" [97]="98" [98]="99" [99]="100")
# ... note ......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................^^^^^^^^^^^^^^^^^^^
And
for n in "${ary[#]}"; do echo $n; done
# or more concisely
printf '%d\n' "${ary[#]}"
excludes 60-80
Something like this maybe?
#!/usr/bin/env bash
arr=({1..100})
exclude=({60..80})
exclude_pattern=$(IFS='|'; printf '%s' "#(${exclude[*]})")
for i in "${arr[#]}"; do
[[ $i == $exclude_pattern ]] && continue
printf '%d\n' "$i"
done
Or create a temp array to build up the elements.
#!/usr/bin/env bash
arr=({1..100})
exclude=({60..80})
exclude_pattern=$(IFS='|'; printf '%s' "#(${exclude[*]})")
for i in "${arr[#]}"; do
[[ $i == $exclude_pattern ]] && continue
included_arr+=("$i")
done
arr=("${included_arr[#]}")
declare -p arr
Related
I'm wondering how to declare a 2D array in bash and then initialize to 0.
In C it looks like this:
int a[4][5] = {0};
And how do I assign a value to an element? As in C:
a[2][3] = 3;
You can simulate them for example with hashes, but need care about the leading zeroes and many other things. The next demonstration works, but it is far from optimal solution.
#!/bin/bash
declare -A matrix
num_rows=4
num_columns=5
for ((i=1;i<=num_rows;i++)) do
for ((j=1;j<=num_columns;j++)) do
matrix[$i,$j]=$RANDOM
done
done
f1="%$((${#num_rows}+1))s"
f2=" %9s"
printf "$f1" ''
for ((i=1;i<=num_rows;i++)) do
printf "$f2" $i
done
echo
for ((j=1;j<=num_columns;j++)) do
printf "$f1" $j
for ((i=1;i<=num_rows;i++)) do
printf "$f2" ${matrix[$i,$j]}
done
echo
done
the above example creates a 4x5 matrix with random numbers and print it transposed, with the example result
1 2 3 4
1 18006 31193 16110 23297
2 26229 19869 1140 19837
3 8192 2181 25512 2318
4 3269 25516 18701 7977
5 31775 17358 4468 30345
The principle is: Creating one associative array where the index is an string like 3,4. The benefits:
it's possible to use for any-dimension arrays ;) like: 30,40,2 for 3 dimensional.
the syntax is close to "C" like arrays ${matrix[2,3]}
Bash doesn't have multi-dimensional array. But you can simulate a somewhat similar effect with associative arrays. The following is an example of associative array pretending to be used as multi-dimensional array:
declare -A arr
arr[0,0]=0
arr[0,1]=1
arr[1,0]=2
arr[1,1]=3
echo "${arr[0,0]} ${arr[0,1]}" # will print 0 1
If you don't declare the array as associative (with -A), the above won't work. For example, if you omit the declare -A arr line, the echo will print 2 3 instead of 0 1, because 0,0, 1,0 and such will be taken as arithmetic expression and evaluated to 0 (the value to the right of the comma operator).
Bash does not support multidimensional arrays.
You can simulate it though by using indirect expansion:
#!/bin/bash
declare -a a0=(1 2 3 4)
declare -a a1=(5 6 7 8)
var="a1[1]"
echo ${!var} # outputs 6
Assignments are also possible with this method:
let $var=55
echo ${a1[1]} # outputs 55
Edit 1: To read such an array from a file, with each row on a line, and values delimited by space, use this:
idx=0
while read -a a$idx; do
let idx++;
done </tmp/some_file
Edit 2: To declare and initialize a0..a3[0..4] to 0, you could run:
for i in {0..3}; do
eval "declare -a a$i=( $(for j in {0..4}; do echo 0; done) )"
done
Another approach is you can represent each row as a string, i.e. mapping the 2D array into an 1D array. Then, all you need to do is unpack and repack the row's string whenever you make an edit:
# Init a 4x5 matrix
a=("00 01 02 03 04" "10 11 12 13 14" "20 21 22 23 24" "30 31 32 33 34")
aset() {
row=$1
col=$2
value=$3
IFS=' ' read -r -a rowdata <<< "${a[$row]}"
rowdata[$col]=$value
a[$row]="${rowdata[#]}"
}
aget() {
row=$1
col=$2
IFS=' ' read -r -a rowdata <<< "${a[$row]}"
echo ${rowdata[$col]}
}
aprint() {
for rowdata in "${a[#]}"; do
echo $rowdata
done
}
echo "Matrix before change"
aprint
# Outputs: a[2][3] == 23
echo "a[2][3] == $( aget 2 3 )"
echo "a[2][3] = 9999"
aset 2 3 9999
# Show result
echo "Matrix after change"
aprint
Outputs:
Matrix before change
00 01 02 03 04
10 11 12 13 14
20 21 22 23 24
30 31 32 33 34
a[2][3] == 23
a[2][3] = 9999
Matrix after change
00 01 02 03 04
10 11 12 13 14
20 21 22 9999 24
30 31 32 33 34
You can also approach this in a much less smarter fashion
q=()
q+=( 1-2 )
q+=( a-b )
for set in ${q[#]};
do
echo ${set%%-*}
echo ${set##*-}
done
of course a 22 line solution or indirection is probably the better way to go and why not sprinkle eval every where to .
2D array can be achieved in bash by declaring 1D array and then elements can be accessed using (r * col_size) + c). Below logic delcares 1D array (str_2d_arr) and prints as 2D array.
col_size=3
str_2d_arr=()
str_2d_arr+=('abc' '200' 'xyz')
str_2d_arr+=('def' '300' 'ccc')
str_2d_arr+=('aaa' '400' 'ddd')
echo "Print 2D array"
col_count=0
for elem in ${str_2d_arr[#]}; do
if [ ${col_count} -eq ${col_size} ]; then
echo ""
col_count=0
fi
echo -e "$elem \c"
((col_count++))
done
echo ""
Output is
Print 2D array
abc 200 xyz
def 300 ccc
aaa 400 ddd
Below logic is very useful to get each row from the above declared 1D array str_2d_arr.
# Get nth row and update to 2nd arg
get_row_n()
{
row=$1
local -n a=$2
start_idx=$((row * col_size))
for ((i = 0; i < ${col_size}; i++)); do
idx=$((start_idx + i))
a+=(${str_2d_arr[${idx}]})
done
}
arr=()
get_row_n 0 arr
echo "Row 0"
for e in ${arr[#]}; do
echo -e "$e \c"
done
echo ""
Output is
Row 0
abc 200 xyz
A way to simulate arrays in bash (it can be adapted for any number of dimensions of an array):
#!/bin/bash
## The following functions implement vectors (arrays) operations in bash:
## Definition of a vector <v>:
## v_0 - variable that stores the number of elements of the vector
## v_1..v_n, where n=v_0 - variables that store the values of the vector elements
VectorAddElementNext () {
# Vector Add Element Next
# Adds the string contained in variable $2 in the next element position (vector length + 1) in vector $1
local elem_value
local vector_length
local elem_name
eval elem_value=\"\$$2\"
eval vector_length=\$$1\_0
if [ -z "$vector_length" ]; then
vector_length=$((0))
fi
vector_length=$(( vector_length + 1 ))
elem_name=$1_$vector_length
eval $elem_name=\"\$elem_value\"
eval $1_0=$vector_length
}
VectorAddElementDVNext () {
# Vector Add Element Direct Value Next
# Adds the string $2 in the next element position (vector length + 1) in vector $1
local elem_value
local vector_length
local elem_name
eval elem_value="$2"
eval vector_length=\$$1\_0
if [ -z "$vector_length" ]; then
vector_length=$((0))
fi
vector_length=$(( vector_length + 1 ))
elem_name=$1_$vector_length
eval $elem_name=\"\$elem_value\"
eval $1_0=$vector_length
}
VectorAddElement () {
# Vector Add Element
# Adds the string contained in the variable $3 in the position contained in $2 (variable or direct value) in the vector $1
local elem_value
local elem_position
local vector_length
local elem_name
eval elem_value=\"\$$3\"
elem_position=$(($2))
eval vector_length=\$$1\_0
if [ -z "$vector_length" ]; then
vector_length=$((0))
fi
if [ $elem_position -ge $vector_length ]; then
vector_length=$elem_position
fi
elem_name=$1_$elem_position
eval $elem_name=\"\$elem_value\"
if [ ! $elem_position -eq 0 ]; then
eval $1_0=$vector_length
fi
}
VectorAddElementDV () {
# Vector Add Element
# Adds the string $3 in the position $2 (variable or direct value) in the vector $1
local elem_value
local elem_position
local vector_length
local elem_name
eval elem_value="$3"
elem_position=$(($2))
eval vector_length=\$$1\_0
if [ -z "$vector_length" ]; then
vector_length=$((0))
fi
if [ $elem_position -ge $vector_length ]; then
vector_length=$elem_position
fi
elem_name=$1_$elem_position
eval $elem_name=\"\$elem_value\"
if [ ! $elem_position -eq 0 ]; then
eval $1_0=$vector_length
fi
}
VectorPrint () {
# Vector Print
# Prints all the elements names and values of the vector $1 on sepparate lines
local vector_length
vector_length=$(($1_0))
if [ "$vector_length" = "0" ]; then
echo "Vector \"$1\" is empty!"
else
echo "Vector \"$1\":"
for ((i=1; i<=$vector_length; i++)); do
eval echo \"[$i]: \\\"\$$1\_$i\\\"\"
###OR: eval printf \'\%s\\\n\' \"[\$i]: \\\"\$$1\_$i\\\"\"
done
fi
}
VectorDestroy () {
# Vector Destroy
# Empties all the elements values of the vector $1
local vector_length
vector_length=$(($1_0))
if [ ! "$vector_length" = "0" ]; then
for ((i=1; i<=$vector_length; i++)); do
unset $1_$i
done
unset $1_0
fi
}
##################
### MAIN START ###
##################
## Setting vector 'params' with all the parameters received by the script:
for ((i=1; i<=$#; i++)); do
eval param="\${$i}"
VectorAddElementNext params param
done
# Printing the vector 'params':
VectorPrint params
read temp
## Setting vector 'params2' with the elements of the vector 'params' in reversed order:
if [ -n "$params_0" ]; then
for ((i=1; i<=$params_0; i++)); do
count=$((params_0-i+1))
VectorAddElement params2 count params_$i
done
fi
# Printing the vector 'params2':
VectorPrint params2
read temp
## Getting the values of 'params2'`s elements and printing them:
if [ -n "$params2_0" ]; then
echo "Printing the elements of the vector 'params2':"
for ((i=1; i<=$params2_0; i++)); do
eval current_elem_value=\"\$params2\_$i\"
echo "params2_$i=\"$current_elem_value\""
done
else
echo "Vector 'params2' is empty!"
fi
read temp
## Creating a two dimensional array ('a'):
for ((i=1; i<=10; i++)); do
VectorAddElement a 0 i
for ((j=1; j<=8; j++)); do
value=$(( 8 * ( i - 1 ) + j ))
VectorAddElementDV a_$i $j $value
done
done
## Manually printing the two dimensional array ('a'):
echo "Printing the two-dimensional array 'a':"
if [ -n "$a_0" ]; then
for ((i=1; i<=$a_0; i++)); do
eval current_vector_lenght=\$a\_$i\_0
if [ -n "$current_vector_lenght" ]; then
for ((j=1; j<=$current_vector_lenght; j++)); do
eval value=\"\$a\_$i\_$j\"
printf "$value "
done
fi
printf "\n"
done
fi
################
### MAIN END ###
################
If each row of the matrix is the same size, then you can simply use a linear array and multiplication.
That is,
a=()
for (( i=0; i<4; ++i )); do
for (( j=0; j<5; ++j )); do
a[i*5+j]=0
done
done
Then your a[2][3] = 3 becomes
a[2*5+3] = 3
This approach might be worth turning into a set of functions, but since you can't pass arrays to or return arrays from functions, you would have to use pass-by-name and sometimes eval. So I tend to file multidimensional arrays under "things bash is simply Not Meant To Do".
One can simply define two functions to write ($4 is the assigned value) and read a matrix with arbitrary name ($1) and indexes ($2 and $3) exploiting eval and indirect referencing.
#!/bin/bash
matrix_write () {
eval $1"_"$2"_"$3=$4
# aux=$1"_"$2"_"$3 # Alternative way
# let $aux=$4 # ---
}
matrix_read () {
aux=$1"_"$2"_"$3
echo ${!aux}
}
for ((i=1;i<10;i=i+1)); do
for ((j=1;j<10;j=j+1)); do
matrix_write a $i $j $[$i*10+$j]
done
done
for ((i=1;i<10;i=i+1)); do
for ((j=1;j<10;j=j+1)); do
echo "a_"$i"_"$j"="$(matrix_read a $i $j)
done
done
Mark Reed suggested a very good solution for 2D arrays (matrix)! They always can be converted in a 1D array (vector). Although Bash doesn't have a native support for 2D arrays, it's not that hard to create a simple ADT around the mentioned principle.
Here is a barebone example with no argument checks, etc, just to keep the solution clear: the array's size is set as two first elements in the instance (documentation for the Bash module that implements a matrix ADT, https://github.com/vorakl/bash-libs/blob/master/src.docs/content/pages/matrix.rst )
#!/bin/bash
matrix_init() {
# matrix_init instance x y data ...
declare -n self=$1
declare -i width=$2 height=$3
shift 3;
self=(${width} ${height} "$#")
}
matrix_get() {
# matrix_get instance x y
declare -n self=$1
declare -i x=$2 y=$3
declare -i width=${self[0]} height=${self[1]}
echo "${self[2+y*width+x]}"
}
matrix_set() {
# matrix_set instance x y data
declare -n self=$1
declare -i x=$2 y=$3
declare data="$4"
declare -i width=${self[0]} height=${self[1]}
self[2+y*width+x]="${data}"
}
matrix_destroy() {
# matrix_destroy instance
declare -n self=$1
unset self
}
# my_matrix[3][2]=( (one, two, three), ("1 1" "2 2" "3 3") )
matrix_init my_matrix \
3 2 \
one two three \
"1 1" "2 2" "3 3"
# print my_matrix[2][0]
matrix_get my_matrix 2 0
# print my_matrix[1][1]
matrix_get my_matrix 1 1
# my_matrix[1][1]="4 4 4"
matrix_set my_matrix 1 1 "4 4 4"
# print my_matrix[1][1]
matrix_get my_matrix 1 1
# remove my_matrix
matrix_destroy my_matrix
For simulating a 2-dimensional array, I first load the first n-elements (the elements of the first column)
local pano_array=()
i=0
for line in $(grep "filename" "$file")
do
url=$(extract_url_from_xml $line)
pano_array[i]="$url"
i=$((i+1))
done
To add the second column, I define the size of the first column and calculate the values in an offset variable
array_len="${#pano_array[#]}"
i=0
while [[ $i -lt $array_len ]]
do
url="${pano_array[$i]}"
offset=$(($array_len+i))
found_file=$(get_file $url)
pano_array[$offset]=$found_file
i=$((i+1))
done
The below code will definitely work provided if you are working on a Mac you have bash version 4. Not only can you declare 0 but this is more of a universal approach to dynamically accepting values.
2D Array
declare -A arr
echo "Enter the row"
read r
echo "Enter the column"
read c
i=0
j=0
echo "Enter the elements"
while [ $i -lt $r ]
do
j=0
while [ $j -lt $c ]
do
echo $i $j
read m
arr[${i},${j}]=$m
j=`expr $j + 1`
done
i=`expr $i + 1`
done
i=0
j=0
while [ $i -lt $r ]
do
j=0
while [ $j -lt $c ]
do
echo -n ${arr[${i},${j}]} " "
j=`expr $j + 1`
done
echo ""
i=`expr $i + 1`
done
I have a config file:
map_a 1234,3788,9940
map_b 9948,8901
map_c
map_d 7789,30400
map_e 499423
map_f
The array variable should content:
Name Attribute 1 Attribute 2 Attribute 3 Attribute ...
---------------------------------------------------------------------------
map_a 1234 3788 9940
map_b 9948 8901
map_c
map_d 7789 30400
map_e 499423
map_f
...
So:
foo[0,0] = map_a
foo[0,1] = 1234
foo[3,2] = 30400
...
How can I achieve this with bash? Or are there recommendations for change the delimiters of the .cfg file? As it's flexible from scratch
Regards
Joe C.
Bash arrays are one-dimensional, but associate arrays may allow you to represent something that looks like 2D array (each key will be the indices combined with ','). Without changing the structure:
#! /bin/bash
declare -A foo
n=0
maxcol=0
IFS=" ,"
while read k v ; do
foo[$n,0]=$k
IFS=', ' read -r -a vv <<< "$v"
i=1
for v1 in ${vv[*]} ; do
foo[$n,$i]=$v1
[ $i -gt $maxcol ] && maxcol=$i
let i=i+1
done
let n=n+1
done < config.txt
for ((i=0; i<n ; i++)) do
for ((j=0 ; j<maxcol ; j++)) do
echo "foo($i,$j)=${foo[$i,$j]}"
done
echo
done
Alternative will be to use the attribute name as the first key, so that it will be possible to query ${foo[map_a,2}} - 2nd attribute of map_a
#! /bin/bash
declare -A foo
n=0
maxcol=0
maxcol=0
IFS=" ,"
while read k v ; do
foo[$n,0]=$k
IFS=', ' read -r -a vv <<< "$v"
i=1
for v1 in ${vv[*]} ; do
# Use key as first index
foo[$k,$i]=$v1
[ $i -gt $maxcol ] && maxcol=$i
let i=i+1
done
let n=n+1
done < config.txt
for i in map_a map_b map_c map_d map_e map_f ; do
for ((j=0 ; j<maxcol ; j++)) do
echo "foo($i,$j)=${foo[$i,$j]}"
done
echo
done
Alright, I've also put maxcol into an array:
declare -A foo
declare -A maxcol
n=0
IFS=" ,"
while read k v
do
foo[$n,0]=$k
IFS=', ' read -r -a vv <<< "$v"
i=1
for v1 in ${vv[*]}
do
foo[$n,$i]=$v1
let i=i+1
done
maxcol[$n]=$i
let n=n+1
done < config.txt
for (( i=0; i<n; i++ ))
do
for (( j=0 ; j<maxcol[$i] ; j++ ))
do
echo "foo($i,$j)=${foo[$i,$j]}"
done
echo "maxcol($i)=${maxcol[$i]}"
echo
done
I think this will fit my needs now perfectly.
I have to make a script that makes the sum of all processes that have PIDS greater than 20. It kind of works but something is going wrong. I know it's something simple, base thing, but I can't get the logic.
For example I have 2 processes, "1504" and "1405". My result of sum is 15041405. How do I have to re-write sum+=${proc[$i]} to make an actual sum, not string attach?
proc=( $(ps | cut -d ' ' -f1) )
nr=$(ps | cut -d ' ' -f1 | wc -l)
sum=0
for (( i=0 ; i<=nr ; i++)); do
[[ ${proc[$i]} -gt 20 ]] && sum+=${proc[$i]}
done
echo $sum
Use a math context. In POSIX sh:
sum=$(( sum + val ))
...or, also valid POSIX:
: "$(( sum += val ))"
...or, in bash:
(( sum += val ))
You can also use much easier-to-read comparison operations in a math context, rather than using -gt inside of a non-math test context. In bash:
(( ${proc[$i]} >= 20 )) && (( sum += ${proc[$i]} ))
...or in POSIX shell (which doesn't support arrays, and so cannot exactly reproduce your sample code):
: "$(( sum += ( val < 20 ) ? 0 : val ))"
If you were trying to do the (more sensible) operation of counting PIDs, I'd consider an implementation more like the following (bash-only and Linux-only, but considerably more efficient):
count=0
for pid_file in /proc/[0-9]*; do
pid=${pid_file##*/}
(( pid > 20 )) && (( count++ ))
done
printf '%s\n' "$count"
...or, to put more of the effort on the glob engine:
# avoid inflating the result with non-matching globs
shopt -s nullglob
# define a function to avoid overwriting the global "$#" array
count_procs() {
set -- /proc/[3-9][0-9] /proc/[0-9][0-9][0-9]*
echo "$#"
}
# ...used as follows:
count_procs
In my script I need to expand an interval, e.g.:
input: 1,5-7
to get something like the following:
output: 1,5,6,7
I've found other solutions here, but they involve python and I can't use it in my script.
Solution with Just Bash 4 Builtins
You can use Bash range expansions. For example, assuming you've already parsed your input you can perform a series of successive operations to transform your range into a comma-separated series. For example:
value1=1
value2='5-7'
value2=${value2/-/..}
value2=`eval echo {$value2}`
echo "input: $value1,${value2// /,}"
All the usual caveats about the dangers of eval apply, and you'd definitely be better off solving this problem in Perl, Ruby, Python, or AWK. If you can't or won't, then you should at least consider including some pipeline tools like tr or sed in your conversions to avoid the need for eval.
Try something like this:
#!/bin/bash
for f in ${1//,/ }; do
if [[ $f =~ - ]]; then
a+=( $(seq ${f%-*} 1 ${f#*-}) )
else
a+=( $f )
fi
done
a=${a[*]}
a=${a// /,}
echo $a
Edit: As #Maxim_united mentioned in the comments, appending might be preferable to re-creating the array over and over again.
This should work with multiple ranges too.
#! /bin/bash
input="1,5-7,13-18,22"
result_str=""
for num in $(tr ',' ' ' <<< "$input"); do
if [[ "$num" == *-* ]]; then
res=$(seq -s ',' $(sed -n 's#\([0-9]\+\)-\([0-9]\+\).*#\1 \2#p' <<< "$num"))
else
res="$num"
fi
result_str="$result_str,$res"
done
echo ${result_str:1}
Will produce the following output:
1,5,6,7,13,14,15,16,17,18,22
expand_commas()
{
local arg
local st en i
set -- ${1//,/ }
for arg
do
case $arg in
[0-9]*-[0-9]*)
st=${arg%-*}
en=${arg#*-}
for ((i = st; i <= en; i++))
do
echo $i
done
;;
*)
echo $arg
;;
esac
done
}
Usage:
result=$(expand_commas arg)
eg:
result=$(expand_commas 1,5-7,9-12,3)
echo $result
You'll have to turn the separated words back into commas, of course.
It's a bit fragile with bad inputs but it's entirely in bash.
Here's my stab at it:
input=1,5-7,10,17-20
IFS=, read -a chunks <<< "$input"
output=()
for chunk in "${chunks[#]}"
do
IFS=- read -a args <<< "$chunk"
if (( ${#args[#]} == 1 )) # single number
then
output+=(${args[*]})
else # range
output+=($(seq "${args[#]}"))
fi
done
joined=$(sed -e 's/ /,/g' <<< "${output[*]}")
echo $joined
Basically split on commas, then interpret each piece. Then join back together with commas at the end.
A generic bash solution using the sequence expression `{x..y}'
#!/bin/bash
function doIt() {
local inp="${#/,/ }"
declare -a args=( $(echo ${inp/-/..}) )
local item
local sep
for item in "${args[#]}"
do
case ${item} in
*..*) eval "for i in {${item}} ; do echo -n \${sep}\${i}; sep=, ; done";;
*) echo -n ${sep}${item};;
esac
sep=,
done
}
doIt "1,5-7"
Should work with any input following the sample in the question. Also with multiple occurrences of x-y
Use only bash builtins
Using ideas from both #Ansgar Wiechers and #CodeGnome:
input="1,5-7,13-18,22"
for s in ${input//,/ }
do
if [[ $f =~ - ]]
then
a+=( $(eval echo {${s//-/..}}) )
else
a+=( $s )
fi
done
oldIFS=$IFS; IFS=$','; echo "${a[*]}"; IFS=$oldIFS
Works in Bash 3
Considering all the other answers, I came up with this solution, which does not use any sub-shells (but one call to eval for brace expansion) or separate processes:
# range list is assumed to be in $1 (e.g. 1-3,5,9-13)
# convert $1 to an array of ranges ("1-3" "5" "9-13")
IFS=,
local range=($1)
unset IFS
list=() # initialize result list
local r
for r in "${range[#]}"; do
if [[ $r == *-* ]]; then
# if the range is of the form "x-y",
# * convert to a brace expression "{x..y}",
# * using eval, this gets expanded to "x" "x+1" … "y" and
# * append this to the list array
eval list+=( {${r/-/..}} )
else
# otherwise, it is a simple number and can be appended to the array
list+=($r)
fi
done
# test output
echo ${list[#]}
I tried to create a shell script, which sum the given numbers. If there is no given parameter, then it tries to read the pipe output, but I get an error.
#!/bin/sh
sum=0
if [ $# -eq 0 ]
then
while read data
do
sum=`expr $sum + $data`
done
else
for (( i = 1 ; i <= $#; i++ ))
do
sum=`expr $sum + ${!i}`
done
fi
echo $sum
This works: sum 10 12 13
But this one doesn't: echo 10 12 13| sum
Thanks in advance,
Here you go (assuming bash, not sh):
#!/bin/bash
sum=0
if (( $# == 0 )); then
# Read line by line
# But each line might consist of separate numbers to be added
# So read each line as an array!
while read -a data; do
# Now data is an array... but if empty, continue
(( ${#data[#]} )) || continue
# Convert this array into a string s, with elements separated by a +
printf -v s "%s+" ${data[#]}
# Append 0 to s (observe that s ended with a +)
s="${s}0"
# Add these numbers to sum
(( sum += s ))
done
else
# If elements come from argument line, do the same!
printf -v s "%s+" $#
# Append 0 to s (observe that s ended with a +)
s="${s}0"
# Add these numbers to obtain sum
(( sum = s ))
fi
echo $sum
You can invoke it thus:
$ echo 10 12 13 | ./sum
35
$ ./sum 10 12 13
35
$ # With several lines and possibly empty lines:
$ { echo 10 12 13; echo; echo 42 22; } | ./sum
99
Hope this helps!
Edit. You might also be interested in learning cool stuff about IFS. I've noticed that people tend to confuse # and * in bash. If you don't know what I'm talking about, then you should use # instead of *, also for array subscripts! In the bash manual, you'll find that when double quoted, $* (or ${array[*]}) expands to all the elements of the array separated by the value of the IFS. This can be useful in our case:
#!/bin/bash
sum=0
if (( $# == 0 )); then
# Read line by line
# But each line might consist of separate numbers to be added
# So read each line as an array!
while read -a data; do
# Now data is an array... but if empty, continue
(( ${#data[#]} )) || continue
# Setting IFS=+ (just for the sum) will yield exactly what I want!
IFS=+ sum=$(( sum + ${data[*]} ))
done
else
# If elements come from argument line, do the same!
# Setting IFS=+ (just for the sum) will yield exactly what I want!
IFS=+ sum=$(( $* ))
fi
echo $sum
Gniourf now exits from teacher mode. :-)