Trying to verify that a string has only lowercase, uppercase, or numbers in it.
if ! [[ "$TITLE" =~ ^[a-zA-Z0-9]+$ ]]; then echo "INVALID"; fi
Thoughts?
* UPDATE *
The variable TITLE currently only has upper case text so it should pass and nothing should be outputted. If however I add a special character to TITLE, the IF statement should catch it and echo INVALID. Currently it does not work. It always echos invalid. I think this is because my regex statement is wrong. I think the way I have it written, its looking for a title that has all three in it.
Bash 4.2.25
The idea is, the user should be able to add any title as long as it only contains uppercase, lowercase or numbers. All other characters should fail.
* UPDATE *
If TITLE = ThisIsAValidTitle it echos invalid.
If TITLE = ThisIs#######InvalidTitle it also echos invalid.
* SOLUTION *
Weird, well it started working when I simplified it down to this:
TEST="Valid0"
if ! [[ "$TEST" =~ [^a-zA-Z0-9] ]]; then
echo "VALID"
else
echo "INVALID"
fi
* REAL SOLUTION *
My variable had spaces in it... DUH
Sorry for the trouble guys...
* FINAL SOLUTION *
This accounts for spaces in titles
if ! [[ "$TITLE" =~ [^a-zA-Z0-9\ ] ]]; then
echo "VALID"
else
echo "INVALID"
fi
I'd invert the logic. Test for invalid characters and echo a warning if at least one is present:
if [[ "$TITLE" =~ [^a-zA-Z0-9] ]]; then
echo "INVALID"
fi
With that said, your original check worked for me, so you probably need to provide more context (i.e. a larger portion of your script).
why cant we use alnum
[[ 'mystring123' =~ [:alnum:] ]] && echo "ok" || echo "no"
the nominated answer is wrong. Because it doesn't check to the end of the string. also it's inverted. as the conditional says: "if the start of the string is valid characters then echo invalid"
[[ $TITLE =~ ^[a-zA-Z0-9_-]{3,20}$ ]] && ret="VALID" || ret="INVALID"
echo $ret
Related
I really don't know what I'm doing.
In variable a, I want to find the first appearance of '$' after the first appearance of 'Bitcoin', and print everything after it until the first newline.
I have the following code:
a = 'something Bitcoin something againe $jjjkjk\n againe something'
if [[ $a =~ .*Bitcoin.*[\$](.*).* ]]; then
echo "${BASH_REMATCH[1]}"
else
echo "no"
fi
In this example I would like to get 'jjjkjk'. All I get is 'no'.
This code might be really flawed, I have no experience in this. I think tho the problem might be with the '$' sign. Please help!
Properly handle newlines in bash with ANSI-C Quoting -- \n sequences become literal newlines.
a=$'something Bitcoin something againe $jjjkjk\n againe something'
regex=$'Bitcoin[^$]*[$]([^\n]+)'
[[ $a =~ $regex ]] && declare -p BASH_REMATCH
declare -ar BASH_REMATCH='([0]="Bitcoin something againe \$jjjkjk" [1]="jjjkjk")'
# .................................................................^^^^^^^^^^^^
To verify the contents contain newlines:
$ printf '%s' "$regex" | od -c
0000000 B i t c o i n [ ^ $ ] * [ $ ] (
0000020 [ ^ \n ] + )
0000026
Here is a working version of your code:
a='something Bitcoin something againe $jjjkjk\n againe something'
r=".*Bitcoin.*[\$]([^\n]*).*"
if [[ $a =~ $r ]]; then
echo "${BASH_REMATCH[1]}"
else
echo "no"
fi
You need to find 'Bitcoin' then find a '$' after it, no matter what is between, so you should use .* operator, also when you want to capture some text until a specific char, the best way is using [^](not) operator, in your case: [^\n] this means capture everything until \n.
Also you had an issue with your variable declaration. a = "..." is not valid, the spaces are waste. so the correct one is 'a=".."`.
Using double quotation is wrong too, this will replaces dollar sign with an empty variable (evaluation)
keyFileName=$1;
for fileExt in "${validTypes[#]}"
do
echo $fileExt;
if [[ $keyFileName == *.$fileExt ]]; then
keyStatus="true";
fi
done;
I am trying to check the file extension of a file passed in against an array of multiple file extensions. However it doesn't seem to be working properly. Any help?
validTypes=(".txt" ".mp3")
keyFileName="$1"
for fileExt in "${validTypes[#]}"
do
echo $fileExt;
if [[ $keyFileName =~ ^.*$fileExt$ ]]; then
keyStatus="true";
echo "Yes"
fi
done;
Effectively, you could change your if statement to either:
if [[ $keyFileName == ?*$fileExt ]] # Glob pattern case, ? denotes single char
or:
if [[ $keyFileName =~ .*$fileExt ]] # Regex case, . denotes single char
Looping over the array to do a regex match on each element seems rather inefficient. You're using regex; it's easy to combine the expressions and avoid looping at all.
Mangling the array into a valid regex is not entirely trivial, though. Here's my attempt:
validTypes=('\.txt' '\.mp3')
fileExtRe=$(printf '|%s' "${validTypes[#]}"
# Trim off the first alternation, add parens and anchor
fileExtRe="(${fileExtRe#?})$"
if [[ $keyFileName =~ $fileExtRe ]]; then
:
Notice how the elements in validTypes are regular expressions now, with the dot escaped to only match a literal dot.
i am pretty new to bash shell scripting (and linux too)... i try to do a simple script which involves some regex for a string given by keyboard from a user.
clear
read -p "Insert e-mail > "
if [[ $REPLY =~ ^[.] ]]
then
echo "ERROR (code 1): e-mail cannot start with \".\""
elif [[ $REPLY =~ .[.]$ ]]
then
echo "ERROR (code 2): e-mail cannot end with \".\""
else
if [[ $REPLY =~ ^[0-9][0-9a-zA-Z!#$%^\&\'*+-]+$ ]] #THIS IS WHERE I NEED HELP
then
echo "Good!"
else
echo "Bad!"
fi
fi
so what i want to do is to make a regex
so that the user cant start with . or end with . (i pretty much did that and its working)...
next what i wanted to do was make the string start with a number and i did that with ^[0-9] (i think this is correct)
and after that..string could be anything like a number 0-9 or letters a-z and A-Z or the next characters: !#$%^&'*+-/
so when user entered 1& (it starts with number and the rest is in the acceptable characters) but it didn't work.. because it need to be \& (at the regex formula).
next the same problem occurred to character ' what i did, was to add again a backslash to regex formula (\') and it worked..
then i tried to do the same with / character (slash character) so what i did was add a backslash / (backslash slash) but when user entered 1/ (it starts with number and the rest are acceptable characters) unfortunately it printed "Bad!" ... it should print Good!..
why is that happening?
i tried \/ and \\/ but still... cant understand why it doesn't work!
Problem is presence of ! in your character class that is doing history expansion.
I suggest declaring your regex beforehand like this:
re="^[0-9][0-9a-zA-Z\!#$%^&/*'+-]+$"
Then use it as:
s='1/'
[[ $s =~ $re ]] && echo "good" || echo "bad"
good
Actually, /s work in character classes just fine:
$ [[ "1/" =~ ^[0-9][/]+$ ]]; echo $?
0
I'm pretty new to bash scripting and regexp and have a question.
I want to check to see if my variable $name starts with a-d, e-h, i-l etc and do some stuff accordingly. If the string starts with "the." or "The." it should check the first letter after the period.
My problem is that if $name consists of "the.anchor" both the a-d0-9 and q-t will be true. Do you guys have any idea what's wrong?
if [[ $name =~ ^([tT]he\.)?[a-dA-D0-9]+ ]]; then
do some stuff
fi
if [[ $name =~ ^([tT]he\.)?[e-hE-H]+ ]]; then
do some stuff
fi
if [[ $name =~ ^([tT]he\.)?[i-lI-L]+ ]]; then
do some stuff
fi
if [[ $name =~ ^([tT]he\.)?[m-pM-P]+ ]]; then
do some stuff
fi
if [[ $name =~ ^([tT]he\.)?[q-tQ-T]+ ]]; then
do some stuff
fi
if [[ $name =~ ^([tT]he\.)?[u-wU-W]+ ]]; then
do some stuff
fi
if [[ $name =~ ^([tT]he\.)?[x-zX-Z]+ ]]; then
do some stuff
fi
Thanks in advance!
Your first part it optional:
([tT]he\.)?
So the.anchor matches the pattern ^([tT]he\.)?[a-dA-D0-9]+ because the the. matches `^([tT]he\.)? and the a matches [a-dA-D0-9]+. It matches ^([tT]he\.)?[q-tQ-T]+ because ^([tT]he\.)? is optional an t matches [q-tQ-T]+. Note not the whole input is consumed by the second pattern, in fact only the first character is grabbed.
You can verify this by having bash echo the match:
echo "${BASH_REMATCH[0]}"
Which should print the.anchor in the first case and t in the second.
You do not have an end anchor on the pattern so only part of the input needs to be matched. If you made the second pattern ^([tT]he\.)?[q-tQ-T]+$ then it would not match.
Alternatively you could make the the first part possessive - ^([tT]he\.)?+. This will mean that if the engine matches the first expression it will not be unmatched. In the latter case ^([tT]he\.)?+ will grab the the. and then not release it when [q-tQ-T]+ fails; this will cause the match to fail.
I figured out a way to fix my problem by using elif statements and putting the q-t part as the last one
I think the ? can be removed as the if statement is already doing the test. The + matches the preceding item at least once and would only be needed if you want to match more than one instance of the letters.
You can do it like this:
if [[ $name =~ ^[tT]he\.[a-dA-D0-9] ]]; then
do some stuff
fi
The condition will only return true if the first character after ^[tT]he\. is [a-dA-D0-9].
However, I tend to think case is a cleaner solution than if statements when matching lists of characters against variables.
case $name in
[tT]he\.[a-dA-D0-9]*)
do some stuff
;;
esac
Got a very simple script which checks barcodes basically. There's two barcodes that have to be checked that they are not confused when being made into a variable.
Basically the first barcode should contain only numbers 0-9, and the second barcode should contain two letters, then some numbers, then two more letters, like AB123456789CD.
If they're confused and read in the wrong order then it plays an error sound. This is what I have so far, the top one's working, but I'm not sure it it's the best solution, and the bottom one doesn't do what I want:
echo -e $BLUE"Please scan the first barcode"$ENDCOLOUR
read -p "Barcode: " BARCODE1
if [[ "$BARCODE1" =~ [a-z] ]] ; then
play -q ./error.wav
else
echo -e $BLUE"Please scan the second barcode"$ENDCOLOUR
read -p "Barcode: " BARCODE1
if [[ "$BARCODE2" =~ [a-z0-9] ]] ; then
play -q ./error.wav
else
echo "'$BARCODE1',$BARCODE2'" >> barcodes.csv
fi
fi
What's wrong? And is there a more optimal means of achieving this?
Only numbers:
if ! [[ $BARCODE1 =~ ^[0-9]+$ ]]; then
Because of the + sign this is going to enter the if statement for empty strings as well. + means one or more times and * means zero or more time.
Two characters, numbers, two characters:
if ! [[ $BARCODE1 =~ ^[a-zA-Z][a-zA-Z][0-9]+[a-zA-Z][a-zA-Z]$ ]]; then
Once again, this is not going to match for strings like 'AABB'. If you think that 'AABB' is a valid barcode, then use this:
if ! [[ $BARCODE1 =~ ^[a-zA-Z][a-zA-Z][0-9]*[a-zA-Z][a-zA-Z]$ ]]; then
EDIT:
Also, if you know exact count of numbers in a barcode, then you could use {n}
if ! [[ $BARCODE1 =~ ^[a-zA-Z]{2}[0-9]{9}[a-zA-Z]{2}$ ]]; then
Which means 2 letters, 9 numbers, 2 letters