I have a simple way to search for multiple substrings in a single string:
if [[ $string = *"string 1"* && $string = *"string 2"* && $string = *"string 3"* ]]
(here searching for string 1, string 2 and string 3 in string).
How can I simplify this, so that there is only one check?
I've tried:
if [[ $string = *"string 1"*"string 2"*"string 3"* ]]
and
if [[ $string = *"string 1*string 2*string 3"* ]]
Note: the three strings specified here will always be in this order, hence why I can simplify it.
In ksh93, you can use the & sub-pattern delimiter.
$ [[ abcdefg == #(*bcd*&*cde*&*efg*) ]]; echo $?
0
$ [[ abcdefg == #(*bcdz*&*cde*&*efg*) ]]; echo $?
1
Only ksh93 has this unfortunately. In mksh, zsh, and bash, with extended matching, the negation sub-pattern allows for this DeMorgan-like equivalence.
$ [[ abcdefg == !(!(*bcd*)|!(*cde*)|!(*efg*)) ]]; echo $?
0
$ [[ abcdefg == !(!(*bcdz*)|!(*cde*)|!(*efg*)) ]]; echo $?
1
To test for just one pattern, see this FAQ
Related
I am trying to parse and validate a string in Bash which is comma separated. The expected input is: X4,Y1,Z5
Conditions: The string should have only X,Y or Z alphabets, followed by any number. The string should not have any special characters other than comma. Please suggest.
X4,Y1,Z5 (This is OK)
Z2,y6,X1 (This is OK)
X3Y6,Z8 (This is not OK)
A1,B2,X8 (This is not OK)
N1P8* (This is not OK)
I have tried the following but this is not working as expected.
if [[ ! $str =~ ['!##$%^&*()_+'] ]] && [[ $str =~ [XYZxyz] ]]; then
echo "OK"
else
echo "Not OK"
fi
I suppose there are additional conditions of the problem that were implied but not emphasized, such as:
The numbers may have more then one digit.
Each of X,Y,Z letters should be used exactly once.
With that in mind, I think this code will do:
if [[ "$1" =~ ^[XxYyZz][0-9]+(,[XxYyZz][0-9]+){2}$ ]] &&
[[ "$1" =~ .*[Xx].* ]] &&
[[ "$1" =~ .*[Yy].* ]] &&
[[ "$1" =~ .*[Zz].* ]]
then
echo OK
else
echo Not OK
fi
Test cases:
#!/usr/bin/env bash
check() {
[[ "$1" =~ ^[XxYyZz][0-9]+(,[XxYyZz][0-9]+){2}$ ]] &&
[[ "$1" =~ .*[Xx].* ]] &&
[[ "$1" =~ .*[Yy].* ]] &&
[[ "$1" =~ .*[Zz].* ]]
}
test_check() {
# code - expected exit code
# value - string to test
while read code value; do
check "$value"
if [[ $? == $code ]]; then
echo -e "\e[1;32mPassed:\e[0m $value"
else
echo -e "\e[1;31mFailed:\e[0m $value"
fi
done
}
test_check <<EOF
0 x1,y2,z3
0 X1,Y2,Z3
1 x,y,z
1 1,2,3
1 1x,2y,3z
0 z1,x2,y3
1 a1,b2,c3
1 x1
1 x1,y2 z1
1 x1,x2
1 x1;y2;z3
1 x1,y2
1 x1,y2,y3
0 x100,Y500,z0
0 x011,y015,z0
1 x1,x2,y3,z4
1 x1,y1,z1 .
EOF
P.S.
If any of the X,Y,Z may appear in the string more than once or not appear at all, then [[ "$str" =~ ^[XxYyZz][0-9]+(,[XxYyZz][0-9]+)*$ ]] should work. I added here + for digits to appear one or more times after the letter, and quoted "$str" in case if there's a space in it (or, to be precise, any character from $IFS variable).
how to make several comparisons in the bash by placing the condition and comparison points next to instead of the long queue ?
that something like this
before :
if [[ $var == "aaa" || $var == "bbb" || $var == "ccc" || $var == "ddd" ]];
then
echo "good";
fi
after (what I want):
if [[ $var==["aaa","bbb","ccc","ddd"] ]];
then
echo "good";
fi
With extended pattern matching:
shopt -s extglob
[[ $var = #(aaa|bbb|ccc|ddd) ]] && echo "good"
Try this using bash regex with the keywork =~:
if [[ $var =~ ^(aaa|bbb|ccc|ddd)$ ]];
then
echo "good";
fi
Edit :
As seen in comments, for real you need to compare int, not strings, so :
((var%3 == 0)) && echo "ok"
Using bash arithmetic
I tried the following but without success
[root#OBAMA~]# bash
[root#OBAMA~]# a=HelloWorld
[root#OBAMA~]# [[ $a == [A-Za-z] ]] && echo "YES ITS STRING"
( the command not prints anything )
[root#OBAMA~]# [[ $a == [A-Z][a-z] ]] && echo "YES ITS STRING"
( the command not prints anything )
Change your command lke below.
$ [[ $a =~ [A-Za-z]+ ]] && echo "YES ITS STRING"
YES ITS STRING
Use =~ operator to test an input string against a regex.
Add + next to the character class, so that it would repeat the previous pattern or token one or more times. Here it's unnecessary.
Add anchors , in-order to do an exact string match. [[ $a =~ [A-Za-z] ]] && echo "YES ITS STRING" alone will print the string YES ITS STRING because the variable a contains atleast an alphabet.
$ a="HelloWorld"
$ [[ $a =~ ^[A-Za-z]+$ ]] && echo "YES ITS STRING"
YES ITS STRING
$ a="Hello World"
$ [[ $a =~ ^[A-Za-z]+$ ]] && echo "YES ITS STRING"
$
how do you define "a string"
[[ -n $a ]] && echo variable a is not empty
[[ $a == *[[:alpha:]]* ]] && echo variable a contains a letter
shopt -s extglob failglob
[[ $a == +([[:alpha:]]) ]] && echo variable a only has letters
Your glob expressions are not matching because your checking that your variable contains only 1 character or 2 characters.
String:
name#gmail.com
Checking for:
#
.com
My code
if [[ $word =~ "#" ]]
then
if [[ $word =~ ".com" || $word =~ ".ca" ]]
My problem
name#.com
The above example gets passed, which is not what I want. How do I check for characters (1 or more) between "#" and ".com"?
You can use a very very basic regex:
[[ $var =~ ^[a-z]+#[a-z]+\.[a-z]+$ ]]
It looks for a string being exactly like this:
at least one a-z char
#
at least one a-z char
.
at least one a-z char
It can get as complicated as you want, see for example Email check regular expression with bash script.
See in action
$ var="a#b.com"
$ [[ $var =~ ^[a-z]+#[a-z]+\.[a-z]+$ ]] && echo "kind of valid email"
kind of valid email
$ var="a#.com"
$ [[ $var =~ ^[a-z]+#[a-z]+\.[a-z]+$ ]] && echo "kind of valid email"
$
why not go for other tools like perl:
> echo "x#gmail.com" | perl -lne 'print $1 if(/#(.*?)\.com/)'
gmail
The glob pattern would be: [[ $word == ?*#?*.#(com|ca) ]]
? matches any single character and * matches zero or more characters
#(p1|p2|p3|...) is an extended globbing pattern that matches one of the given patterns. This requires:
shopt -s extglob
testing:
$ for word in #.com #a.ca a#.com a#b.ca a#b.org; do
echo -ne "$word\t"
[[ $word == ?*#?*.#(com|ca) ]] && echo matches || echo does not match
done
#.com does not match
#a.ca does not match
a#.com does not match
a#b.ca matches
a#b.org does not match
When given a string I want to search for a substring which matches two characters (9&0. 0 should be the last character in that substring) and exactly two characters in between them
string="asd20 92x0x 72x0 YX92s0 0xx0 92x0x"
#I want to select substring YX92s0 from that above string
for var in $string
do
if [[ "$var" == *9**0 ]]; then
echo $var // Should print YX92s0 only
fi
done
Obviously this above command doesn't work.
You match each element against the pattern *9??0. There are several ways you can do this; here's one that uses the string to set the positional parameters in a subshell, then iterates over them in a for loop:
( set -- $string
for elt; do [[ $elt == *9??0 ]] && { echo "found"; exit; }; done )
string="asd20 92x0x 72x0 X92s0 0xx0"
if [[ $string =~ [[:space:]].?9.{2}0[[:space:]] ]]; then
echo "found"
fi
Or better, taking advantage of word spliting :
string="asd20 92x0x 72x0 X92s0 0xx0"
for s in $string; do
if [[ $s =~ (.*9.{2}0) ]]; then
echo "${BASH_REMATCH[1]} found"
fi
done
This is regex with bash.