Using the above syntax, we can create an approach where we extract substring "elements" from the string by deleting the substrings up to or after the delimiter. # and %% delete the longest possible matching substring. # and % delete the shortest possible matching substring from the start and end of the string respectively, and (The lack of this approach in any solution posted so far is the main reason I'm writing this answer ) $ # drops substring from first occurrence of `SubStr` to end of string Note that * is a wildcard that stands for zero or more characters: There is a syntax used in many shells for deleting substrings of a string from the first or last occurrence of a pattern. However, we don't need to use arrays to loop over "elements" of a string. If you can't use bash, or if you want to write something that can be used in many different shells, you often can't use bashisms - and this includes the arrays we've been using in the solutions above. In newer versions of bash, you can also play with the command mapfile: mapfile -td \ fields ', done. Or you could drop each field from the array after processing using a shifting approach, which I like: while doĪnd if you just want a simple printout of the array, you don't even need to loop over it: printf "> \n" > Once the array is defined, you can use a simple loop to process each field (or, rather, each element in the array you've now defined): # expands to return every element of `fields` array as a separate argument Note that read is the quickest way to do the split because there are no forks or external resources called. (We can also display the contents of these variables using declare -p:) declare -p IN fields This means we can do the above in just one line: IFS=\ read -a fields ") In newer versions of bash, prefixing a command with an IFS definition changes the IFS for that command only and resets it to the previous value immediately afterwards.
# save original IFS value so we can restore it later The IFS, among other things, tells bash which character(s) it should treat as a delimiter between elements when defining an array: Name " In pure bash, we can create an array with elements split by a temporary value for IFS (the input field separator). Split string based on delimiter in bash (version >=4.2) The string to be split in the above question is: will use a modified version of this string to ensure that my solution is robust to strings containing whitespace, which could break other solutions: Name "
In particular, arrays, associative arrays, and pattern substitution, which are used in the solutions in this post as well as others in the thread, are bashisms and may not work under other shells that many people use.įor instance: on my Debian GNU/Linux, there is a standard shell called dash I know many people who like to use another shell called ksh and there is also a special tool called busybox with his own shell interpreter ( ash).įor posix shell compatible answer, go to last part of this answer! Requested string However, it's important to first note that bash has many special features (so-called bashisms) that won't work in any other shell. There are a lot of different ways to do this in bash. I only got the first string when printing it in loop, without brackets around $IN it works. RE: IFS solution, I tried this and it works, I keep the old IFS and then restore it: x in $mails2
I am not sure what happened with that answer, how do you reset IFS back to default? Output: > was a solution involving setting Internal_field_separator (IFS) to. If they are elements of an array that's even better.Īfter suggestions from the answers below, I ended up with the following which is what I was after: #!/usr/bin/env $IN | tr " " "\n") I have this string stored in a variable: I would like to split the strings by delimiter so that I have: don't necessarily need the ADDR1 and ADDR2 variables.
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