I'm trying to match any strings that start with /John/ but does not contain / after /John/
if
[ $string == /John/[!/]+ ]; then ....
fi
This is what I got and it doesn't seem to be working.
So I tried
if
[[ $string =~ ^/John/[!/]+$ ]]; then ....
fi
It still didn't work, and so I changed it to
if
[[ $string =~ /John/[^/] ]]; then ....
fi
It worked but will match with all the strings that has / behind /John/ too.
For bash you want [[ $string =~ /John/[^/]*$ ]] -- the end-of-line anchor ensures there are no slashes after the last acceptable slash.
How about "the string starts with '/John/' and doesn't contain any slashes after '/John/'"?
[[ $string = /John/* && $string != /John/*/* ]]
Or you could compare against a parameter expansion that only expands if the conditions are met. This says "after stripping off everything including and after the last slash, the string is /John":
[[ ${string%/*} = /John ]]
In fact, this last solution is the only entirely POSIXLY_STRICT one I can come up with without multiple test expressions.
[ "${string%/*}" = /John ]
By the way, your problem is probably simply be using double-equals inside a single-bracket test expression. bash actually does accept them inside double-bracket test expressions, but a single equals is a better idea.
You can also use plain old grep:
string='/John Lennon/Yoko Ono'
if echo "$string" | grep -q "/John[^/]" ; then
echo "matched"
else
echo "no match found"
fi
This only fails if /John is at the very end of the string... if that's a possibility then you can tweak to handle that case, for instance:
string='/John Lennon/Yoko Ono'
if echo "$string" | grep -qP "(/John[^/])|(/John$)" ; then
echo "matched"
else
echo "no match found"
fi
Not sure what language you're using, but normal negative character classes are prefixed with a ^
e.g.
[^/]
You can also put in start/end qualifiers (clojure example, so Java's regex engine). Usually ^ at beginning and $ at end.
user => (re-matches #"^/[a-zA-Z]+[^/]$" "/John/")
nil
Related
I am trying to compare strings against a list of other strings read from a file.
However some of the strings in the file contain wildcard characters (both ? and *) which need to be taken into account when matching.
I am probably missing something but I am unable to see how to do it
Eg.
I have strings from file in an array which could be anything alphanumeric (and include commas and full stops) with wildcards : (a?cd, xy, q?hz, j,h-??)
and I have another string I wish to compare with each item in the list in turn. Any of the strings may contain spaces.
so what I want is something like
teststring="abcdx.rubb ish,y"
matchstrings=("a?cd" "*x*y" "q?h*z" "j*,h-??")
for i in "${matchstrings[#]}" ; do
if [[ "$i" == "$teststring" ]]; then # this test here is the problem
<do something>
else
<do something else>
fi
done
This should match on the second "matchstring" but not any others
Any help appreciated
Yes; you just have the two operands to == reversed; the glob goes on the right (and must not be quoted):
if [[ $teststring == $i ]]; then
Example:
$ i=f*
$ [[ foo == $i ]] && echo pattern match
pattern match
If you quote the parameter expansion, the operation is treated as a literal string comparison, not a pattern match.
$ [[ foo == "$i" ]] || echo "foo != f*"
foo != f*
Spaces in the pattern are not a problem:
$ i="foo b*"
$ [[ "foo bar" == $i ]] && echo pattern match
pattern match
You can do this even completely within POSIX, since case alternatives undergo parameter substitution:
#!/bin/sh
teststring="abcdx.rubbish,y"
while IFS= read -r matchstring; do
case $teststring in
($matchstring) echo "$matchstring";;
esac
done << "EOF"
a?cd
*x*y
q?h*z
j*,h-??
EOF
This outputs only *x*y as desired.
I have a script when you select a desktop file, but when I run this case function:
File=$(yad --file);
if [[ "$File" =~ *".desktop" ]]; then
echo "yes"
else
echo "no"
if
and i try this :
File=$(yad --file);
case $File in
*.desktop )
echo "yes"
;;
* )
echo "no"
;;
esac
it's always telling me that I have to try again I don't know what's the problem, can anyone help me?
I am not exactly sure what this script is supposed to do, but try this:
File="$(Yad --file)"
if [[ "$File" =~ .*[.]desktop$ ]]; then
echo "yes"
else
echo "no"
fi
Bash regular expression matching (=~) uses extended regular expressions, not glob expressions. To designate any sequence of zero or more characters, you need to use .*. The . means "any character", and the * means zero or more times. [.] designates a literal period, avoiding the "any character" meaning of . used alone. I also added an end-of-line anchor ($). This forces the pattern to match from the end of the filename, as you probably would want when matching with the extension.
There also is an error in your first line. There has to be no space between the $ sign and parentheses. And to close an if block, you need to use fi.
You can use glob-style matching with bash conditionals, just use an equal sign :
if [[ "$File" = *.desktop ]]; then
I have a shell script that needs to check if a file name matches a certain regex, but it always shows "not match". Can anyone let me know what's wrong with my code?
fileNamePattern=abcd_????_def_*.txt
realFilePath=/data/file/abcd_12bd_def_ghijk.txt
if [[ $realFilePath =~ $fileNamePattern ]]
then
echo $realFilePath match $fileNamePattern
else
echo $realFilePath not match $fileNamePattern
fi
There is a confusion between regexes and the simpler "glob"/"wildcard"/"normal" patterns – whatever you want to call them. You're using the latter, but call it a regex.
If you want to use a pattern, you should
Quote it when assigning1:
fileNamePattern="abcd_????_def_*.txt"
You don't want anything to expand quite yet.
Make it match the complete path. This doesn't match:
$ mypath="/mydir/myfile1.txt"
$ mypattern="myfile?.txt"
$ [[ $mypath == $mypattern ]] && echo "Matches!" || echo "Doesn't match!"
Doesn't match!
But after extending the pattern to start with *:
$ mypattern="*myfile?.txt"
$ [[ $mypath == $mypattern ]] && echo "Matches!" || echo "Doesn't match!"
Matches!
The first one doesn't match because it matches only the filename, but not the complete path. Alternatively, you could use the first pattern, but remove the rest of the path with parameter expansion:
$ mypattern="myfile?.txt"
$ mypath="/mydir/myfile1.txt"
$ echo "${mypath##*/}"
myfile1.txt
$ [[ ${mypath##*/} == $mypattern ]] && echo "Matches!" || echo "Doesn't match!"
Matches!
Use == and not =~, as shown in the above examples. You could also use the more portable = instead, but since we're already using the non-POSIX [[ ]] instead of [ ], we can as well use ==.
If you want to use a regex, you should:
Write your pattern as one: ? and * have a different meaning in regexes; they modify what they stand after, whereas in glob patterns, they can stand on their own (see the manual). The corresponding pattern would become:
fileNameRegex='abcd_.{4}_def_.*\.txt'
and could be used like this:
$ mypath="/data/file/abcd_12bd_def_ghijk.txt"
$ [[ $mypath =~ $fileNameRegex ]] && echo "Matches!" || echo "Doesn't match!"
Matches!
Keep your habit of writing the regex into a separate parameter and then use it unquoted in the conditional operator [[ ]], or escaping gets very messy – it's also more portable across Bash versions.
The BashGuide has a great article about the different types of patterns in Bash.
Notice that quoting your parameters is almost always a good habit. It's not required in conditional expressions in [[ ]], and actually suppresses interpretation of the right-hand side as a pattern or regex. If you were using [ ] (which doesn't support regexes and patterns anyway), quoting would be required to avoid unexpected side effects of special characters and empty strings.
1 Not exactly true in this case, actually. When assigning to a variable, the manual says that the following happens:
[...] tilde expansion, parameter and variable expansion, command substitution, arithmetic expansion, and quote removal [...]
i.e., no pathname (glob) expansion. While in this very case using
fileNamePattern=abcd_????_def_*.txt
would work just as well as the quoted version, using quotes prevents surprises in many other cases and is required as soon as you have a blank in the pattern.
Use RegExs instead of wildcards:
{ ~ } » fileNamePattern="abcd_...._def_.*\.txt" ~
{ ~ } » realFilePath=/data/file/abcd_12bd_def_ghijk.txt ~
{ ~ } » if [[ $realFilePath =~ $fileNamePattern ]] ~
\ then
\ echo $realFilePath match $fileNamePattern
\ else
\ echo $realFilePath not match $fileNamePattern
\ fi
Output:
/data/file/abcd_12bd_def_ghijk.txt match abcd_...._def_.*\.txt
How can I check for a string in a file path in bash? I am trying:
if [[$(echo "${filePathVar}" | sed 's#//#:#g#') == *"File.java"* ]]
to replace all forward slashes with a colon (:) in the path. It's not working. Bash is seeing the file path string as a file path and throws the error "No such file or directory". The intention is for it to see the file path as a string.
Example: filePathVar could be
**/myloc/src/File.java
in which case the check should return true.
Please note that I am writing this script inside a Jenkins job as a build step.
Updates as of 12/15/15
The following returns Not found, which is wrong.
#!/bin/bash
sources="**/src/TESTS/A.java **/src/TESTS/B.java"
if [[ "${sources}" = ~B.java[^/]*$ ]];
then
echo "Found!!"
else
echo "Not Found!!"
fi
The following returns Found which also also wrong (removed the space around the comparator =).
#!/bin/bash
sources="**/src/TESTS/A.java **/src/TESTS/C.java"
if [[ "${sources}"=~B.java[^/]*$ ]];
then
echo "Found!!"
else
echo "Not Found!!"
fi
The comparison operation is clearly not working.
It is easier to use bash's builtin regex matching facility:
$ filePathVar=/myLoc/src/File.java
if [[ "$filePathVar" =~ File.java[^/]*$ ]]; then echo Match; else echo No Match; fi
Match
Inside [[...]], the operator =~ does regex matching. The regular expression File.java[^/]* matches any string that contains File.java optionally followed by anything except /.
It worked in a simpler way as below:
#!/bin/bash
sources="**/src/TESTS/A.java **/src/TESTS/B.java"
if [[ $sources == *"A.java"* ]]
then
echo "Found!!"
else
echo "Not Found!!"
fi
I am attempting to check for proper formatting at the start of a string in a bash script.
The expected format is like the below where the string must always begin with "ABCDEFG-" (exact letters and order) and the numbers would vary but be at least 3 digits. Everything after the 3rd digit is a do not care.
Expected start of string: "ABCDEFG-1234"
I am using the below code snippet.
[ $(echo "$str" | grep -E "ABCDEFG-[0-9][0-9][0-9]") ] && echo "yes"
str1 = "ABCDEFG-1234"
str2 = "ABCDEFG-1234 - Some more text"
When I use str1 in place of str everything works ok and yes is printed.
When I use str2 in place of str i get the below error
[: ABCDEFG-1234: unary operator expected
I am pretty new to working with bash scripts so any help would be appreciated.
If this is bash, you have no reason to use grep for this at all; the shell has built-in regular expression support.
re="ABCDEFG-[0-9][0-9][0-9]"
[[ $str =~ $re ]] && echo "yes"
That said, you might want your regex to be anchored if you want a match in the beginning rather than anywhere in the content:
re="^ABCDEFG-[0-9][0-9][0-9]"
[[ $str =~ $re ]] && echo "yes"
That said, this doesn't need to be an ERE at all -- a glob-style pattern match would also be adequate:
if [[ $str = ABCDEFG-[0-9][0-9][0-9]* ]]; then echo "yes"; fi
Try grep -E "ABCDEFG-[0-9][0-9][0-9].*"