How to split a string in shell and get the last field

Question

Suppose I have the string 1:2:3:4:5 and I want to get its last field (5 in this case). How do I do that using Bash? I tried cut, but I don't know how to specify the last field with -f.

Perennial

Answer 1

You can use string operators:

$ foo=1:2:3:4:5
$ echo ${foo##*:}
5

This trims everything from the front until a ':', greedily.

${foo  <-- from variable foo
  ##   <-- greedy front trim
  *    <-- matches anything
  :    <-- until the last ':'
 }

Adieu

While this is working for the given problem, the answer of William below (https://mcmap.net/q/66528/-how-to-split-a-string-in-shell-and-get-the-last-field) also returns 5 if the string is 1:2:3:4:5: (while using the string operators yields an empty result). This is especially handy when parsing paths that could contain (or not) a finishing / character. – Jalousie

How would you then do the opposite of this? to echo out '1:2:3:4:'? – Gahnite

And how does one keep the part before the last separator? Apparently by using ${foo%:*}. # - from beginning; % - from end. #, % - shortest match; ##, %% - longest match. – Habitude

If i want to get the last element from path, how should I use it? echo ${pwd##*/} does not work. – Jeramie

@Jeramie that command sees pwd as a variable. Try dir=$(pwd); echo ${dir##*/}. Works for me! – Sheply

@Adieu How do I use dot (.) as a delimiter? – Salo

@Stan even shorter is echo ${$(pwd)##*/} – Schmidt

This worked well for getting the name of the file at the end of a URL for me, by replacing : with /. – Sword

Answer 2

Another way is to reverse before and after cut:

$ echo ab:cd:ef | rev | cut -d: -f1 | rev
ef

This makes it very easy to get the last but one field, or any range of fields numbered from the end.

Trevar

This answer is nice because it uses 'cut', which the author is (presumably) already familiar. Plus, I like this answer because I am using 'cut' and had this exact question, hence finding this thread via search. – Stud

Some cut-and-paste fodder for people using spaces as delimiters: echo "1 2 3 4" | rev | cut -d " " -f1 | rev – Asylum

the rev | cut -d -f1 | rev is so clever! Thanks! Helped me a bunch (my use case was rev | -d ' ' -f 2- | rev – Tangerine

I always forget about rev, was just what I needed! cut -b20- | rev | cut -b10- | rev – Sorrow

I ended up with this solution, my attempt o cut file paths with "awk -F "/" '{print $NF}' " broke somewhat for me, as file names including white spaces got also cut apart – Monarchism

Beware: rev is not safe with multi-byte Unicode characters! Therefore some corner cases might not work with rev. – Bead

@t0r0X: Are you sure? On my machine, with LC_ALL=en_US.utf8, running echo 'hé' | rev correctly returns éh. I have to run echo 'hé' | LC_ALL=C rev to get an error: rev: stdin: Invalid or incomplete multibyte or wide character. – Trevar

except that: -sh: rev: command not found on my NAS, seems like rev is not so common, otherwise I agree it better answers a question about cut – Quasijudicial

Fantastic! I wanted to grab only the top-level and second-level domains from a domain name. With cut, I can turn things like www.google.com into google.com! – Interval

If you want to extract the TLD out of a list of domains: cat domains.txt | rev | cut -d. -f2 | rev | sort | uniq -c | sort -rn – Ozonize

This is by far the best answer if you are processing a whole file using cat + grep, thanks a lot for coming up with it!! – Son

Answer 3

It's difficult to get the last field using cut, but here are some solutions in awk and perl

echo 1:2:3:4:5 | awk -F: '{print $NF}'
echo 1:2:3:4:5 | perl -F: -wane 'print $F[-1]'

Hylophagous

great advantage of this solution over the accepted answer: it also matches paths that contain or do not contain a finishing / character: /a/b/c/d and /a/b/c/d/ yield the same result (d) when processing pwd | awk -F/ '{print $NF}'. The accepted answer results in an empty result in the case of /a/b/c/d/ – Jalousie

@Jalousie In case of AWK solution, on GNU bash, version 4.3.48(1)-release that's not true, as it matters whenever you have trailing slash or not. Simply put AWK will use / as delimiter, and if your path is /my/path/dir/ it will use value after last delimiter, which is simply an empty string. So it's best to avoid trailing slash if you need to do such a thing like I do. – Destructor

How would I get the substring UNTIL the last field? – Heraclitean

@Heraclitean There are some quirks, but something like awk '{$NF=""; print $0}' FS=: OFS=: often works well enough. – Hylophagous

Answer 4

Assuming fairly simple usage (no escaping of the delimiter, for example), you can use grep:

$ echo "1:2:3:4:5" | grep -oE "[^:]+$"
5

Breakdown - find all the characters not the delimiter ([^:]) at the end of the line ($). -o only prints the matching part.

Offhand

-E means using extended syntax; [^...] means anything but the listed char(s); + one or more such hits (will take the maximum possible length for the pattern; this item is a gnu extension) - for the example the separating char(s) are the colon. – Progressist

Answer 5

You could try something like this if you want to use cut:

echo "1:2:3:4:5" | cut -d ":" -f5

You can also use grep try like this :

echo " 1:2:3:4:5" | grep -o '[^:]*$'

Curculio

Your second command was useful to me. Would you break it down so I can understand it better? Thank you. – Revitalize

Answer 6

One way:

var1="1:2:3:4:5"
var2=${var1##*:}

Another, using an array:

var1="1:2:3:4:5"
saveIFS=$IFS
IFS=":"
var2=($var1)
IFS=$saveIFS
var2=${var2[@]: -1}

Yet another with an array:

var1="1:2:3:4:5"
saveIFS=$IFS
IFS=":"
var2=($var1)
IFS=$saveIFS
count=${#var2[@]}
var2=${var2[$count-1]}

Using Bash (version >= 3.2) regular expressions:

var1="1:2:3:4:5"
[[ $var1 =~ :([^:]*)$ ]]
var2=${BASH_REMATCH[1]}

Sternpost

Answer 7

$ echo "a b c d e" | tr ' ' '\n' | tail -1
e

Simply translate the delimiter into a newline and choose the last entry with tail -1.

Conceivable

It will fail if the last item contains a \n, but for most cases is the most readable solution. – Hirst

Answer 8

Using sed:

$ echo '1:2:3:4:5' | sed 's/.*://' # => 5

$ echo '' | sed 's/.*://' # => (empty)

$ echo ':' | sed 's/.*://' # => (empty)
$ echo ':b' | sed 's/.*://' # => b
$ echo '::c' | sed 's/.*://' # => c

$ echo 'a' | sed 's/.*://' # => a
$ echo 'a:' | sed 's/.*://' # => (empty)
$ echo 'a:b' | sed 's/.*://' # => b
$ echo 'a::c' | sed 's/.*://' # => c

Hybridism

given the output of many utilities is in the form of the original file name followed by colon (:) followed by the utility's output (${path}:${output}), this is incredibly useful for adding your own control character like TAB $'\t' or unit separator $'\037' etc. after that final colon. example for adding a TAB at the final colon of file output: file ~/yourPath/* | sed "s/\(.*:\)\(.*\)/\1"$'\t'"\2/" – Illuminati

Answer 9

There are many good answers here, but still I want to share this one using basename :

 basename $(echo "a:b:c:d:e" | tr ':' '/')

However it will fail if there are already some '/' in your string. If slash / is your delimiter then you just have to (and should) use basename.

It's not the best answer but it just shows how you can be creative using bash commands.

Deflexed

Answer 10

If your last field is a single character, you could do this:

a="1:2:3:4:5"

echo ${a: -1}
echo ${a:(-1)}

Check string manipulation in bash.

Miramirabeau

This doesn't work: it gives the last character of a, not the last field. – Constancy

True, that's the idea, if you know the length of the last field it's good. If not you have to use something else... – Miramirabeau

Answer 11

Using Bash.

$ var1="1:2:3:4:0"
$ IFS=":"
$ set -- $var1
$ eval echo  \$${#}
0

Crispin

Could have used echo ${!#} instead of eval echo \$${#}. – Signory

Answer 12

Regex matching in sed is greedy (always goes to the last occurrence), which you can use to your advantage here:

$ foo=1:2:3:4:5
$ echo ${foo} | sed "s/.*://"
5

Delaminate

Answer 13

echo "a:b:c:d:e"|xargs -d : -n1|tail -1

First use xargs split it using ":",-n1 means every line only have one part.Then,pring the last part.

Jokjakarta

Answer 14

A solution using the read builtin:

IFS=':' read -a fields <<< "1:2:3:4:5"
echo "${fields[4]}"

Or, to make it more generic:

echo "${fields[-1]}" # prints the last item

Soybean

Answer 15

for x in `echo $str | tr ";" "\n"`; do echo $x; done

Haakon

This runs into problems if there is whitespace in any of the fields. Also, it does not directly address the question of retrieving the last field. – Dewain

Answer 16

improving from @mateusz-piotrowski and @user3133260 answer,

echo "a:b:c:d::e:: ::" | tr ':' ' ' |  xargs | tr ' ' '\n' | tail -1

first, tr ':' ' ' -> replace ':' with whitespace

then, trim with xargs

after that, tr ' ' '\n' -> replace remained whitespace to newline

lastly, tail -1 -> get the last string

Marleah

If you want to contribute an answer according to How to Answer please edit to make that more obvious. You can provide an answer based on an existing answer; giving credit to the exsting answers author is then very appropriate, thanks for doing that. I do however have trouble identifying the answer you are reffering to. Please use the link you get from the "Share" link beneath that answer to add an unambigous link here. – Yaelyager

You know about the commenting privilege which you do not have, so well that you can even put it into words. You are aware of the rule meta.stackexchange.com/questions/214173/… . In that situation please do not decide to misuse a different mechanism (an answer) for something it is not meant for and which you are not allowed yet to do. – Yaelyager

As it’s currently written, your answer is unclear. Please edit to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers in the help center. – Infestation

Thanks for the reminder @Yunnosch, as i am not a native english speaker, i may make mistakes, for all this time using SO just seeking/reading for answers of questions and not answering questions. – Marleah

You only describe the code behaviour on a level which (with some experiece) is clear by the code itself. Please explain what it avhieves, i.e. wha the improvement is. – Yaelyager

sorry, as i am a rather forgetful person. so, the improvement to what i last remember is, to avoid failing if it has empty value between colon (:) or whitespaces. – Marleah

Answer 17

For those that comfortable with Python, https://github.com/Russell91/pythonpy is a nice choice to solve this problem.

$ echo "a:b:c:d:e" | py -x 'x.split(":")[-1]'

From the pythonpy help: -x treat each row of stdin as x.

With that tool, it is easy to write python code that gets applied to the input.

Edit (Dec 2020): Pythonpy is no longer online. Here is an alternative:

$ echo "a:b:c:d:e" | python -c 'import sys; sys.stdout.write(sys.stdin.read().split(":")[-1])'

it contains more boilerplate code (i.e. sys.stdout.read/write) but requires only std libraries from python.

Adhesive