read in bash on whitespace-delimited file without empty fields collapsing

by

Sure

IFS=,
echo $'one\t\tthree' | tr \\11 , | (
  read one two three
  printf '<%s> ' "$one" "$two" "$three"; printf '\n'
)

I’ve rearranged the example just a bit, but only to make it work in any Posix shell.

Update: Yeah, it seems that white space is special, at least if it’s in IFS. See the second half of this paragraph from bash(1):

   The shell treats each character of IFS as a delimiter, and  splits  the
   results of the other expansions into words on these characters.  If IFS
   is unset, or its value is exactly <space><tab><newline>,  the  default,
   then  any  sequence  of IFS characters serves to delimit words.  If IFS
   has a value other than the default, then sequences  of  the  whitespace
   characters  space  and  tab are ignored at the beginning and end of the
   word, as long as the whitespace character is in the value  of  IFS  (an
   IFS whitespace character).  Any character in IFS that is not IFS white-
   space, along with any adjacent IFS whitespace  characters,  delimits  a
   field.   A  sequence  of IFS whitespace characters is also treated as a
   delimiter.  If the value of IFS is null, no word splitting occurs.

More Related Contents:

  1. How do I split a string on a delimiter in Bash?
  2. Looping over pairs of values in bash [duplicate]
  3. How to merge every two lines into one from the command line?
  4. Why can’t I specify an environment variable and echo it in the same command line?
  5. Find and Replace Inside a Text File from a Bash Command
  6. Can ${var} parameter expansion expressions be nested in bash?
  7. “unary operator expected” error in Bash if condition
  8. Difference between single and double square brackets in Bash
  9. How to echo shell commands as they are executed
  10. Random number from a range in a Bash Script
  11. bash: shortest way to get n-th column of output
  12. Calling shell functions with xargs
  13. Why piping input to “read” only works when fed into “while read …” construct? [duplicate]
  14. Openssh Private Key to RSA Private Key
  15. Parse out key=value pairs into variables
  16. bash variable interpolation separate variables by a hyphen or underscore
  17. How to kill all subprocesses of shell?
  18. Check if all of multiple strings or regexes exist in a file
  19. How to get the PID of a process that is piped to another process in Bash?
  20. How to reset COMP_WORDBREAKS without affecting other completion script?
  21. Fastest possible grep
  22. Bash scripting, multiple conditions in while loop
  23. Divide two variables in bash
  24. Printing asterisk (“*”) in bash shell
  25. Get exit code from subshell through the pipes
  26. What does the curly-brace syntax ${var%.*} mean?
  27. “Command not found” when attempting integer equality in bash
  28. using bash (sed/awk) to extract rows AND columns in CSV files?
  29. What does the –ntasks or -n tasks does in SLURM?
  30. How can I format the output of a bash command in neat columns

Leave a Comment