Length of string in bash

Question

How do you get the length of a string stored in a variable and assign that to another variable   myvar  some string  echo    myvar      11   How do you set another variable to the output 11

User · Answer

You can use   MYSTRING  abc123  MYLENGTH   printf   s    MYSTRING    wc -c     wc -c or wc --bytes for byte counts   Unicode characters are counted with 2  3 or more bytes  wc -m or wc --chars for character counts   Unicode characters are counted single until they use more bytes

User · Answer

If you want to use this with command line or function arguments  make sure you use size    1  instead of size     1   The second one may be  more instinctual but is incorrect syntax

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UTF-8 string length  In addition to fedorqui s correct answer  I would like to show the difference between string length and byte length   myvar  G  n  ralit  s  chrlen    myvar  oLang  LANG oLcAll  LC ALL LANG C LC ALL C bytlen    myvar  LANG  oLang LC ALL  oLcAll printf   s is  d char len  but  d bytes len  n     myvar    chrlen  bytlen   will render   G  n  ralit  s is 11 char len  but 14 bytes len    you could even have a look at stored chars   myvar  G  n  ralit  s  chrlen    myvar  oLang  LANG oLcAll  LC ALL LANG C LC ALL C bytlen    myvar  printf -v myreal   q    myvar  LANG  oLang LC ALL  oLcAll printf   s has  d chars   d bytes    s   n     myvar    chrlen  bytlen   myreal    will answer   G  n  ralit  s has 11 chars  14 bytes     G 303 251n 303 251ralit 303 251s      Nota  According to Isabell Cowan s comment  I ve added setting to  LC ALL along with  LANG   Length of an argument  Argument work same as regular variables  strLen         local bytlen sreal oLang  LANG oLcAll  LC ALL     LANG C LC ALL C     bytlen    1      printf -v sreal  q   1      LANG  oLang LC ALL  oLcAll     printf  String   s  is  d bytes  but  d chars len   s  n    1   bytlen    1    sreal      will work as  strLen th  or  me String  th  or  me  is 10 bytes  but 8 chars len    th 303 251or 303 250me    Useful printf correction tool   If you   for string in G  n  ralit  s Language Th  or  me F  vrier   Left      Yin Yang    do     printf   -  -14s is  2d char length n     string       string  done   -  G  n  ralit  s  is 11 char length  -  Language      is  8 char length  -  Th  or  me    is  8 char length  -  F  vrier      is  7 char length  -  Left        is  7 char length  -  Yin Yang    is 10 char length   Not really pretty    For this  there is a little function   strU8DiffLen           local bytlen oLang  LANG oLcAll  LC ALL     LANG C LC ALL C     bytlen    1      LANG  oLang LC ALL  oLcAll     return     bytlen -    1         Then now   for string in G  n  ralit  s Language Th  or  me F  vrier   Left      Yin Yang    do     strU8DiffLen   string      printf   -  -   14     s is  2d chars length  but uses  2d bytes n               string      string        string         done    -  G  n  ralit  s   is 11 chars length  but uses 14 bytes  -  Language      is  8 chars length  but uses  8 bytes  -  Th  or  me      is  8 chars length  but uses 10 bytes  -  F  vrier       is  7 chars length  but uses  8 bytes  -  Left          is  7 chars length  but uses  9 bytes  -  Yin Yang      is 10 chars length  but uses 12 bytes   Unfortunely  this is not perfect   But there left some strange UTF-8 behaviour  like double-spaced chars  zero spaced chars  reverse deplacement and other that could not be as simple     Have a look at diffU8test sh or diffU8test sh txt for more limitations

User · Answer

I wanted the simplest case  finally this is a result   echo -n  Tell me the length of this sentence     wc -m  36

User · Answer

Here is couple of ways to calculate length of variable    echo    VAR  echo -n  VAR   wc -m echo -n  VAR   wc -c printf  VAR   wc -m expr length  VAR expr  VAR          and to set the result in another variable just assign above command with back quote into another variable as following   otherVar  echo -n  VAR   wc -m     echo  otherVar   http   techopsbook blogspot in 2017 09 how-to-find-length-of-string-variable html

User · Answer

Using your example provided   KISS  Keep it simple stupid  size    myvar  echo  size

User · Answer

To get the length of a string stored in a variable  say   myvar  some string  size    myvar     To confirm it was properly saved  echo it     echo   size  11

User · Answer

In response to the post starting      If you want to use this with command line or function arguments      with the code    size    1    There might be the case where you just want to check for a zero length argument and have no need to store a variable  I believe you can use this sort of syntax   if   -z   1     then      zero length argument  else      non-zero length fi   See GNU and wooledge for a more complete list of Bash conditional expressions

[bash] Length of string in bash

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