The title could suck, not sure what a good way to explain it is.
This might both be a bad idea, but I'm trying to make a kind of ninite-thing for Linux/Ubuntu. I want a correctly styled name to appear in the list where you check what you want to install, whereas the package name is needed for installation. I have tried to achieve this, but not had much luck.
The menu/interactive bits have been taken from this site. I have only added arrays as options, and a few other modifications. I am very new to this, and it is mainly a project for learning.
#!/bin/bash
# customize with your own.
#Packages
filezilla=("FileZilla" "filezilla" "ftp")
nmap=("Nmap" "nmap" "network_tools")
linssider=("LinSSIDer" "linssider" "network_tools")
wireshark=("Wireshark" "wireshark" "network_tools")
atom=("Atom" "atom" "editor")
vim=("Vim" "vim" "editor")
steam=("Steam" "steam" "chat")
streamlink=("Streamlink GUI" "streamlink" "media")
whois=("Whois" "whois" "network_tools")
htop=("Htop" "htop" "monitoring")
traceroute=("Traceroute" "traceroute" "network_tools")
options=(
"${filezilla[0]}"
#echo Network Tools
"${nmap[0]}"
"${linssider[0]}"
"${wireshark[0]}"
"${whois[0]}"
"${htop[0]}"
"${traceroute[0]}"
#echo "Text Editor"
"${atom[0]}"
"${vim[0]}"
#echo "Chat"
"${steam[0]}"
#echo "Media"
"${streamlink[0]}"
#select all in category x
#select all in cat y
)
#render list
clear
menu() {
echo ""
echo "What do you want to install:"
for i in ${!options[#]}; do
printf "%3d%s) %s\n" $((i+1)) "${choices[i]:- }" "${options[i]}"
done
[[ "$msg" ]] && echo "$msg"; :
}
#selecting
prompt="Check an option (again to uncheck, ENTER when done): "
while menu && read -rp "$prompt" num && [[ "$num" ]]; do
clear
[[ "$num" != *[![:digit:]]* ]] &&
(( num > 0 && num <= ${#options[#]} )) ||
{ msg="Invalid option: $num"; continue; }
((num--)); msg="${options[num]} was ${choices[num]:+un}checked"
[[ "${choices[num]}" ]] && choices[num]="" || choices[num]="+"
done
#what was selected
printf "You selected"; msg=" nothing"
for i in ${!options[#]}; do
[[ "${choices[i]}" ]] && { printf " \n%s" "${options[i]}"; msg=""; }
echo ${choices[1]}
done
echo "$msg"
#install selected
#sudo apt install -y update ${choices[1]}
Related
Using:
set -o nounset
Having an indexed array like:
myArray=( "red" "black" "blue" )
What is the shortest way to check if element 1 is set?
I sometimes use the following:
test "${#myArray[#]}" -gt "1" && echo "1 exists" || echo "1 doesn't exist"
I would like to know if there's a preferred one.
How to deal with non-consecutive indexes?
myArray=()
myArray[12]="red"
myArray[51]="black"
myArray[129]="blue"
How to quick check that 51 is already set for example?
How to deal with associative arrays?
declare -A myArray
myArray["key1"]="red"
myArray["key2"]="black"
myArray["key3"]="blue"
How to quick check that key2 is already used for example?
To check if the element is set (applies to both indexed and associative array)
[ "${array[key]+abc}" ] && echo "exists"
Basically what ${array[key]+abc} does is
if array[key] is set, return abc
if array[key] is not set, return nothing
References:
See Parameter Expansion in Bash manual and the little note
if the colon is omitted, the operator tests only for existence [of parameter]
This answer is actually adapted from the answers for this SO question: How to tell if a string is not defined in a bash shell script?
A wrapper function:
exists(){
if [ "$2" != in ]; then
echo "Incorrect usage."
echo "Correct usage: exists {key} in {array}"
return
fi
eval '[ ${'$3'[$1]+muahaha} ]'
}
For example
if ! exists key in array; then echo "No such array element"; fi
From man bash, conditional expressions:
-v varname
True if the shell variable varname is set (has been assigned a value).
example:
declare -A foo
foo[bar]="this is bar"
foo[baz]=""
if [[ -v "foo[bar]" ]] ; then
echo "foo[bar] is set"
fi
if [[ -v "foo[baz]" ]] ; then
echo "foo[baz] is set"
fi
if [[ -v "foo[quux]" ]] ; then
echo "foo[quux] is set"
fi
This will show that both foo[bar] and foo[baz] are set (even though the latter is set to an empty value) and foo[quux] is not.
New answer
From version 4.2 of bash (and newer), there is a new -v option to built-in test command.
From version 4.3, this test could address element of arrays.
array=([12]="red" [51]="black" [129]="blue")
for i in 10 12 30 {50..52} {128..131};do
if [ -v 'array[i]' ];then
echo "Variable 'array[$i]' is defined"
else
echo "Variable 'array[$i]' not exist"
fi
done
Variable 'array[10]' not exist
Variable 'array[12]' is defined
Variable 'array[30]' not exist
Variable 'array[50]' not exist
Variable 'array[51]' is defined
Variable 'array[52]' not exist
Variable 'array[128]' not exist
Variable 'array[129]' is defined
Variable 'array[130]' not exist
Variable 'array[131]' not exist
Note: regarding ssc's comment, I've single quoted 'array[i]' in -v test, in order to satisfy shellcheck's error SC2208. This seem not really required here, because there is no glob character in array[i], anyway...
This work with associative arrays in same way:
declare -A aArray=([foo]="bar" [bar]="baz" [baz]=$'Hello world\041')
for i in alpha bar baz dummy foo test;do
if [ -v 'aArray[$i]' ];then
echo "Variable 'aArray[$i]' is defined"
else
echo "Variable 'aArray[$i]' not exist"
fi
done
Variable 'aArray[alpha]' not exist
Variable 'aArray[bar]' is defined
Variable 'aArray[baz]' is defined
Variable 'aArray[dummy]' not exist
Variable 'aArray[foo]' is defined
Variable 'aArray[test]' not exist
With a little difference:In regular arrays, variable between brackets ([i]) is integer, so dollar symbol ($) is not required, but for associative array, as key is a word, $ is required ([$i])!
Old answer for bash prior to V4.2
Unfortunately, bash give no way to make difference betwen empty and undefined variable.
But there is some ways:
$ array=()
$ array[12]="red"
$ array[51]="black"
$ array[129]="blue"
$ echo ${array[#]}
red black blue
$ echo ${!array[#]}
12 51 129
$ echo "${#array[#]}"
3
$ printf "%s\n" ${!array[#]}|grep -q ^51$ && echo 51 exist
51 exist
$ printf "%s\n" ${!array[#]}|grep -q ^52$ && echo 52 exist
(give no answer)
And for associative array, you could use the same:
$ unset array
$ declare -A array
$ array["key1"]="red"
$ array["key2"]="black"
$ array["key3"]="blue"
$ echo ${array[#]}
blue black red
$ echo ${!array[#]}
key3 key2 key1
$ echo ${#array[#]}
3
$ set | grep ^array=
array=([key3]="blue" [key2]="black" [key1]="red" )
$ printf "%s\n" ${!array[#]}|grep -q ^key2$ && echo key2 exist || echo key2 not exist
key2 exist
$ printf "%s\n" ${!array[#]}|grep -q ^key5$ && echo key5 exist || echo key5 not exist
key5 not exist
You could do the job without the need of externals tools (no printf|grep as pure bash), and why not, build checkIfExist() as a new bash function:
$ checkIfExist() {
eval 'local keys=${!'$1'[#]}';
eval "case '$2' in
${keys// /|}) return 0 ;;
* ) return 1 ;;
esac";
}
$ checkIfExist array key2 && echo exist || echo don\'t
exist
$ checkIfExist array key5 && echo exist || echo don\'t
don't
or even create a new getIfExist bash function that return the desired value and exit with false result-code if desired value not exist:
$ getIfExist() {
eval 'local keys=${!'$1'[#]}';
eval "case '$2' in
${keys// /|}) echo \${$1[$2]};return 0 ;;
* ) return 1 ;;
esac";
}
$ getIfExist array key1
red
$ echo $?
0
$ # now with an empty defined value
$ array["key4"]=""
$ getIfExist array key4
$ echo $?
0
$ getIfExist array key5
$ echo $?
1
What about a -n test and the :- operator?
For example, this script:
#!/usr/bin/env bash
set -e
set -u
declare -A sample
sample["ABC"]=2
sample["DEF"]=3
if [[ -n "${sample['ABC']:-}" ]]; then
echo "ABC is set"
fi
if [[ -n "${sample['DEF']:-}" ]]; then
echo "DEF is set"
fi
if [[ -n "${sample['GHI']:-}" ]]; then
echo "GHI is set"
fi
Prints:
ABC is set
DEF is set
tested in bash 4.3.39(1)-release
declare -A fmap
fmap['foo']="boo"
key='foo'
# should echo foo is set to 'boo'
if [[ -z "${fmap[${key}]}" ]]; then echo "$key is unset in fmap"; else echo "${key} is set to '${fmap[${key}]}'"; fi
key='blah'
# should echo blah is unset in fmap
if [[ -z "${fmap[${key}]}" ]]; then echo "$key is unset in fmap"; else echo "${key} is set to '${fmap[${key}]}'"; fi
Reiterating this from Thamme:
[[ ${array[key]+Y} ]] && echo Y || echo N
This tests if the variable/array element exists, including if it is set to a null value. This works with a wider range of bash versions than -v and doesn't appear sensitive to things like set -u. If you see a "bad array subscript" using this method please post an example.
This is the easiest way I found for scripts.
<search> is the string you want to find, ASSOC_ARRAY the name of the variable holding your associative array.
Dependign on what you want to achieve:
key exists:
if grep -qe "<search>" <(echo "${!ASSOC_ARRAY[#]}"); then echo key is present; fi
key exists not:
if ! grep -qe "<search>" <(echo "${!ASSOC_ARRAY[#]}"); then echo key not present; fi
value exists:
if grep -qe "<search>" <(echo "${ASSOC_ARRAY[#]}"); then echo value is present; fi
value exists not:
if ! grep -qe "<search>" <(echo "${ASSOC_ARRAY[#]}"); then echo value not present; fi
I wrote a function to check if a key exists in an array in Bash:
# Check if array key exists
# Usage: array_key_exists $array_name $key
# Returns: 0 = key exists, 1 = key does NOT exist
function array_key_exists() {
local _array_name="$1"
local _key="$2"
local _cmd='echo ${!'$_array_name'[#]}'
local _array_keys=($(eval $_cmd))
local _key_exists=$(echo " ${_array_keys[#]} " | grep " $_key " &>/dev/null; echo $?)
[[ "$_key_exists" = "0" ]] && return 0 || return 1
}
Example
declare -A my_array
my_array['foo']="bar"
if [[ "$(array_key_exists 'my_array' 'foo'; echo $?)" = "0" ]]; then
echo "OK"
else
echo "ERROR"
fi
Tested with GNU bash, version 4.1.5(1)-release (i486-pc-linux-gnu)
For all time people, once and for all.
There's a "clean code" long way, and there is a shorter, more concise, bash centered way.
$1 = The index or key you are looking for.
$2 = The array / map passed in by reference.
function hasKey ()
{
local -r needle="${1:?}"
local -nr haystack=${2:?}
for key in "${!haystack[#]}"; do
if [[ $key == $needle ]] ;
return 0
fi
done
return 1
}
A linear search can be replaced by a binary search, which would perform better with larger data sets. Simply count and sort the keys first, then do a classic binary halving of of the haystack as you get closer and closer to the answer.
Now, for the purist out there that is like "No, I want the more performant version because I may have to deal with large arrays in bash," lets look at a more bash centered solution, but one that maintains clean code and the flexibility to deal with arrays or maps.
function hasKey ()
{
local -r needle="${1:?}"
local -nr haystack=${2:?}
[ -n ${haystack["$needle"]+found} ]
}
The line [ -n ${haystack["$needle"]+found} ]uses the ${parameter+word} form of bash variable expansion, not the ${parameter:+word} form, which attempts to test the value of a key, too, which is not the matter at hand.
Usage
local -A person=(firstname Anthony lastname Rutledge)
if hasMapKey "firstname" person; then
# Do something
fi
When not performing substring expansion, using the form described
below (e.g., ‘:-’), Bash tests for a parameter that is unset or null.
Omitting the colon results in a test only for a parameter that is
unset. Put another way, if the colon is included, the operator tests
for both parameter’s existence and that its value is not null; if the
colon is omitted, the operator tests only for existence.
${parameter:-word}
If parameter is unset or null, the expansion of word is substituted. Otherwise, the value of parameter is substituted.
${parameter:=word}
If parameter is unset or null, the expansion of word is assigned to parameter. The value of parameter is then substituted. Positional
parameters and special parameters may not be assigned to in this way.
${parameter:?word}
If parameter is null or unset, the expansion of word (or a message to that effect if word is not present) is written to the standard
error and the shell, if it is not interactive, exits. Otherwise, the
value of parameter is substituted. ${parameter:+word}
If parameter is null or unset, nothing is substituted, otherwise the expansion of word is substituted.
https://www.gnu.org/savannah-checkouts/gnu/bash/manual/bash.html#Shell-Parameter-Expansion
If $needle does not exist expand to nothing, otherwise expand to the non-zero length string, "found". This will make the -n test succeed if the $needle in fact does exist (as I say "found"), and fail otherwise.
Both in the case of arrays and hash maps I find the easiest and more straightforward solution is to use the matching operator =~.
For arrays:
myArray=("red" "black" "blue")
if [[ " ${myArray[#]} " =~ " blue " ]]; then
echo "blue exists in myArray"
else
echo "blue does not exist in myArray"
fi
NOTE: The spaces around the array guarantee the first and last element can match. The spaces around the value guarantee an exact match.
For hash maps, it's actually the same solution since printing a hash map as a string gives you a list of its values.
declare -A myMap
myMap=(
["key1"]="red"
["key2"]="black"
["key3"]="blue"
)
if [[ " ${myMap[#]} " =~ " blue " ]]; then
echo "blue exists in myMap"
else
echo "blue does not exist in myMap"
fi
But what if you would like to check whether a key exists in a hash map? In the case you can use the ! operator which gives you the list of keys in a hash map.
if [[ " ${!myMap[#]} " =~ " key3 " ]]; then
echo "key3 exists in myMap"
else
echo "key3 does not exist in myMap"
fi
I get bad array subscript error when the key I'm checking is not set. So, I wrote a function that loops over the keys:
#!/usr/bin/env bash
declare -A helpList
function get_help(){
target="$1"
for key in "${!helpList[#]}";do
if [[ "$key" == "$target" ]];then
echo "${helpList["$target"]}"
return;
fi
done
}
targetValue="$(get_help command_name)"
if [[ -z "$targetvalue" ]];then
echo "command_name is not set"
fi
It echos the value when it is found & echos nothing when not found. All the other solutions I tried gave me that error.
I am trying to compare an array with a value and print an error statement if the match is not found.
arraylist="$(ls new-dir/ | cut -d' ' -f1)"
For example, this stores values such as small, large and medium which are the files present in new-dir.
The value to be compared with will be entered by the user viz. var
I have tried something like following:
(for i in "${arraylist[#]}"; do [[ "$i" == "$var"]] && exit 0; done) && echo "found" || echo "not found"
Also tried, however, doesn't work:
arraylist="$(ls new-dir/ | cut -d' ' -f1)"
count=0
for((i=0; i<${#arraylist[#]}; i++)); do
if [ "$arraylist[$i]" == "$var" ] ; then
count=1
fi
done
if [ $count -eq 0 ]; then
echo "Not found"
fi
Is there any other way to do this comparison?
This code works. Just replace arraylist with your array.
arraylist=('hello' 'world')
var='hello'
count=0
for i in "${arraylist[#]}"
do
if [ "$i" == "$var" ]; then
count=1
fi
done
if [ $count -eq 0 ]; then
echo "Not found"
fi
To extract the first "word" from each filename, I'd do
declare -A prefixes
cd new-dir
for file in *; do
read -r prefix _ <<< "$file"
prefixes["$prefix"]=1
done
cd -
then to look for a match:
# $var is somehow provided
result=""
for p in "${!prefixes[#]}"; do
if [[ $p == "$var" ]]; then
result=found
break
fi
done
echo "${result:-not found}"
This requires bash v4.0+ for the use of an associative array.
If you have bash v4.3+ you can do
[[ -v prefixes[$var] ]] && echo found || echo not found
Alternately:
shopt -s nullglob
files=( new-dir/"$var "* )
(( ${#files[#]} > 0 )) && echo found || echo not found
This is what shell programming is about. Keep it simple :
Array1=( "item1" "item2" "item3" "item-4" )
var="item3"
count=$(echo ${Array1[#]} | tr ' ' '\n' | awk '$1 == "'"$var"'"{print $0}' | wc -l)
[ $count -eq 0 ] && echo "Not found" || echo "found"
The arraylist might be an array with just one index.
The command:
arraylist="$(ls new-dir/ | cut -d' ' -f1)"
might just assign whole "ls new-dir" output to ${arraylist[0]}
You can check the index value in an array by echo ${arraylist[1]} (to confirm).
Try changing the command to generate an array for a list of files/dirs to:
arraylist=($(ls new-dir/))
The complete script:
arraylist=($(ls new-dir/))
(for i in "${arraylist[#]}"; do [[ "$i" == "$var" ]] && exit 0; done) && echo "found" || echo "not found"
You can also ignore the whole array assignment and just use subshell-command in for loop, eg:
(for i in $(ls -1 new-dir/); do [[ "$i" == "$var" ]] && exit 0; done) && echo "found" || echo "not found"
Remember, no quotes " around $(ls -1 new-dir/)
Another one-liner without any array or loops:
ls -1 new-dir/ | grep -q "$var" && echo "found" || echo "not found"
Edit:
As #M. Nejat Aydin suggested, use [[ -e new-dir/$var ]] && echo "found" || echo "Not found" and do not use ls in the script.
I have a script that I'll be using in a system where the first three positional parameters are reserved, but I want to pass other parameters to the script to be used as variables. I can set default values for the variables, but if a parameter is included, I want that to take precedence. Here's a very basic script to illustrate:
#!/bin/bash
param1="$1"
param2="$2"
param3="$3"
param4="default4"
if [[ "$param4" == "" ]] && [[ "$4" == "" ]]; then
echo "A value was not specified for parameter 4. Script cannot execute. Exiting..."
exit 1
elif [[ "$4" != "" ]]; then
param4="$4"
else
echo "The built-in value for parameter 4 will be used in the script."
fi
echo "$param1"
echo "$param2"
echo "$param3"
echo "$param4"
If I run script a b c the output I get is:
The built-in value for parameter 4 will be used in the script.
a
b
c
default4
If I run script a b c d then the output is:
a
b
c
d
This is all well and good, but if I have 5-6 different parameters, I don't want to have to repeat the if..fi block that many times for each parameter.
So I've been trying to use a for loop to iterate through the parameters, but I haven't had much luck. The best attempt I came up with was:
#!/bin/bash
param1="$1"
param2="$2"
param3="$3"
param4="default4"
param5="default5"
param6="default6"
param7="default7"
defaultArray=( param4 param5 param6 param7 )
passedArray=( '$4' '$5' '$6' '$7' )
for (( i=0; i<${#defaultArray[#]}; i++ ));
do
if [[ "${defaultArray[$i]}" == "" ]] && [[ "${passedArray[$i]}" == "" ]]; then
echo "A value was not specified for parameter $((i+4)). Script cannot execute. Exiting..."
exit 1
elif [[ "${passedArray[$i]}" != "" ]]; then
eval "${defaultArray[$i]}"='"${passedArray[$i]}"'
else
echo "The built-in value for parameter $((i+4)) will be used in the script."
fi
done
echo "$param1"
echo "$param2"
echo "$param3"
echo "$param4"
echo "$param5"
echo "$param6"
echo "$param7"
But when I run this script a b c, or script a b c d, and whether or not I delete the default values in the script, I always get:
a
b
c
$4
$5
$6
$7
I think this because I needed to single-quote the positional parameter names in passedArray or else they just blank out, but then that hard-codes their names rather than the passed value.
Is there a way of doing this, or does trying to assign a positional parameter to a variable in an array and/or a for loop just not work? The thing I'm going to try next is a function, but I'm not sure that'd work any better...
Change
param4="default4"
if [[ "$param4" == "" ]] && [[ "$4" == "" ]]; then
echo "A value was not specified for parameter 4. Script cannot execute. Exiting..."
exit 1
elif [[ "$4" != "" ]]; then
param4="$4"
else
echo "The built-in value for parameter 4 will be used in the script."
fi
To:
if [[ ! -z $4 ]]; then
param4="$4"
else
param4="default4"
echo "The built-in value for parameter 4 will be used in the script."
fi
In your version of code, the first part of the if condition would never execute because param4 is already set just before if.
A more elegant and consiste way of doing this, given that you are using a default value for param4 anyway is:
param4=${4:-default4} # use default as "default4" unless $4 is set
For the second problem, your suspicion is right - single quotes won't expand the positional variables in the array assignment. So, change it to:
passedArray=( "$4" "$5" "$6" "$7" )
Your loops seems OK, except for this:
elif [[ "${passedArray[$i]}" != "" ]]; then
eval "${defaultArray[$i]}"='"${passedArray[$i]}"'
Why use eval here? You can say:
defaultArray[$i]=${passedArray[$i]}
So I'm developing a simple Address book and its going well.
It uses a singular text file to store all its information.
At the minute i can searh the file for a specific string, not a problem.
I'm pretty sure i can get it to delete a string based on a users input, thats kind of easy but i thought for extra snazziness it would be
a neat idea if I could grab the output of the search term - a multi-line output say - and store each new line into an array, each assigned a number.
From there the user could specify they would like to delete the line based on their input.
So far this is the 'delete' script:
ADDRESSBOOK=~/Documents/Address-Book/add_data.txt
export ADDRESSBOOK
echo "=============================== Delete a Record ==============================="
echo "==============================================================================="
echo "============ Search A Record, then delete it! Type 'exit' to exit ============="
exit=0
search(){
while [ $exit -ne 1 ]
do
echo "Find something for me to delete"
echo -n "-----------------------> "
read searchTerm
if [ "$searchTerm" = "exit" ]
then
exit=1
else
searchOutput=$(grep $searchTerm*.$ $ADDRESSBOOK | sort)
echo "$searchOutput"
fi
done
exit 0
}
search
The address book automatically adds each record with /n so it displays each record on a new line anyway.
Is it possible to take the $searchRecord variable and pass that to an array?
And before I go wrapping my head around arrays, is this even the best approach to take for what I'm trying to do?
I am currently trying something along the lines of
if [ "$searchTerm" = "exit" ]
then
exit=1
else
searchOutput=$(grep $searchTerm*.$ $ADDRESSBOOK | sort)
echo {$searchOutput[*] '/n' }
fi
the '/n' is to TRY and get the records to each appear on a new line. Any advice guys?
Try something like:
l=$(grep $searchTerm $ADDRESSBOOK | \
sort | { \
n=0; \
while read a; \
do echo "searchOutput[$n]=\"$a\";" ; \
n=$((n + 1)) ; \
done; \
})
eval $l
for line in "${searchOutput[#]}"
do
echo $line
done
while read -p 'Find something for me to delete> ' searchTerm
[[ $searchTerm != 'exit' ]] do readarray -t searchOutput < <(grep -i -w "$searchTerm" "$ADDRESSBOOK" | sort)
if ((${#searchOutput[#]}>0)); then
PS3="Select line to delete: "
select line in "${searchOutput[#]}"; do
[[ -z $line ]] && break
line=$(fgrep -nx "$line" "$ADDRESSBOOK")
sed -i ${line%%:*}d "$ADDRESSBOOK"
echo "Deleting line" $line
done
elif [ $searchTerm = "exit" ]
then
exit=1
else
echo "------------- Could Not Find > " $searchTerm
exit=1
fi
done
exit 0
}
This question already has answers here:
Check if a Bash array contains a value
(41 answers)
Closed 2 years ago.
I was wondering if there is an efficient way to check if an element is present within an array in Bash? I am looking for something similar to what I can do in Python, like:
arr = ['a','b','c','d']
if 'd' in arr:
do your thing
else:
do something
I've seen solutions using associative array for bash for Bash 4+, but I am wondering if there is another solution out there.
Please understand that I know the trivial solution is to iterate in the array, but I don't want that.
You could do:
if [[ " ${arr[*]} " == *" d "* ]]; then
echo "arr contains d"
fi
This will give false positives for example if you look for "a b" -- that substring is in the joined string but not as an array element. This dilemma will occur for whatever delimiter you choose.
The safest way is to loop over the array until you find the element:
array_contains () {
local seeking=$1; shift
local in=1
for element; do
if [[ $element == "$seeking" ]]; then
in=0
break
fi
done
return $in
}
arr=(a b c "d e" f g)
array_contains "a b" "${arr[#]}" && echo yes || echo no # no
array_contains "d e" "${arr[#]}" && echo yes || echo no # yes
Here's a "cleaner" version where you just pass the array name, not all its elements
array_contains2 () {
local array="$1[#]"
local seeking=$2
local in=1
for element in "${!array}"; do
if [[ $element == "$seeking" ]]; then
in=0
break
fi
done
return $in
}
array_contains2 arr "a b" && echo yes || echo no # no
array_contains2 arr "d e" && echo yes || echo no # yes
For associative arrays, there's a very tidy way to test if the array contains a given key: The -v operator
$ declare -A arr=( [foo]=bar [baz]=qux )
$ [[ -v arr[foo] ]] && echo yes || echo no
yes
$ [[ -v arr[bar] ]] && echo yes || echo no
no
See 6.4 Bash Conditional Expressions in the manual.
Obvious caveats aside, if your array was actually like the one above, you could do
if [[ ${arr[*]} =~ d ]]
then
do your thing
else
do something
fi
Initialize array arr and add elements
set variable to search for SEARCH_STRING
check if your array contains element
arr=()
arr+=('a')
arr+=('b')
arr+=('c')
SEARCH_STRING='b'
if [[ " ${arr[*]} " == *"$SEARCH_STRING"* ]];
then
echo "YES, your arr contains $SEARCH_STRING"
else
echo "NO, your arr does not contain $SEARCH_STRING"
fi
If array elements don't contain spaces, another (perhaps more readable) solution would be:
if echo ${arr[#]} | grep -q -w "d"; then
echo "is in array"
else
echo "is not in array"
fi
array=("word" "two words") # let's look for "two words"
using grep and printf:
(printf '%s\n' "${array[#]}" | grep -x -q "two words") && <run_your_if_found_command_here>
using for:
(for e in "${array[#]}"; do [[ "$e" == "two words" ]] && exit 0; done; exit 1) && <run_your_if_found_command_here>
For not_found results add || <run_your_if_notfound_command_here>
As bash does not have a built-in value in array operator and the =~ operator or the [[ "${array[#]" == *"${item}"* ]] notation keep confusing me, I usually combine grep with a here-string:
colors=('black' 'blue' 'light green')
if grep -q 'black' <<< "${colors[#]}"
then
echo 'match'
fi
Beware however that this suffers from the same false positives issue as many of the other answers that occurs when the item to search for is fully contained, but is not equal to another item:
if grep -q 'green' <<< "${colors[#]}"
then
echo 'should not match, but does'
fi
If that is an issue for your use case, you probably won't get around looping over the array:
for color in "${colors[#]}"
do
if [ "${color}" = 'green' ]
then
echo "should not match and won't"
break
fi
done
for color in "${colors[#]}"
do
if [ "${color}" = 'light green' ]
then
echo 'match'
break
fi
done
Here's another way that might be faster, in terms of compute time, than iterating. Not sure. The idea is to convert the array to a string, truncate it, and get the size of the new array.
For example, to find the index of 'd':
arr=(a b c d)
temp=`echo ${arr[#]}`
temp=( ${temp%%d*} )
index=${#temp[#]}
You could turn this into a function like:
get-index() {
Item=$1
Array="$2[#]"
ArgArray=( ${!Array} )
NewArray=( ${!Array%%${Item}*} )
Index=${#NewArray[#]}
[[ ${#ArgArray[#]} == ${#NewArray[#]} ]] && echo -1 || echo $Index
}
You could then call:
get-index d arr
and it would echo back 3, which would be assignable with:
index=`get-index d arr`
FWIW, here's what I used:
expr "${arr[*]}" : ".*\<$item\>"
This works where there are no delimiters in any of the array items or in the search target. I didn't need to solve the general case for my applicaiton.