Replace whitespaces with tabs in linux

Question

How do I replace whitespaces with tabs in linux in a given text file?

Answer 1

Use the unexpand(1) program

---

UNEXPAND(1)                      User Commands                     UNEXPAND(1)  NAME        unexpand - convert spaces to tabs  SYNOPSIS        unexpand [OPTION]... [FILE]...  DESCRIPTION        Convert  blanks in each FILE to tabs, writing to standard output.  With        no FILE, or when FILE is -, read standard input.         Mandatory arguments to long options are  mandatory  for  short  options        too.         -a, --all               convert all blanks, instead of just initial blanks         --first-only               convert only leading sequences of blanks (overrides -a)         -t, --tabs=N               have tabs N characters apart instead of 8 (enables -a)         -t, --tabs=LIST               use comma separated LIST of tab positions (enables -a)         --help display this help and exit         --version               output version information and exit . . . STANDARDS        The expand and unexpand utilities conform to IEEE Std 1003.1-2001        (``POSIX.1''). 

Answer 2

I think you can try with awk

awk -v OFS="\t" '$1=$1' file1 

or SED if you preffer

sed 's/[:blank:]+/,/g' thefile.txt > the_modified_copy.txt 

or even tr

tr -s '\t' < thefile.txt | tr '\t' ' ' > the_modified_copy.txt 

or a simplified version of the tr solution sugested by Sam Bisbee

tr ' ' \\t < someFile > someFile