how to remove the first two columns in a file using shell awk sed whatever

Question

I have a file with many lines in each line there are many columns fields  separated by blank     the numbers of columns in each line are different I want to remove the first two columns how to

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This might work for you  GNU sed    sed -r  s           2     file   or for columns separated by one or more white spaces   sed -r  s    S  s   2     file

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Here s one way to do it with Awk that s relatively easy to understand   awk   print substr  0  index  0   3       This is a simple awk command with no pattern  so action inside    is run for every input line    The action is to simply prints the substring starting with the position of the 3rd field     0  the whole input line  3  3rd field index in  find   returns the position of find in string in substr string  start   return a substring starting at index start   If you want to use a different delimiter  such as comma  you can specify it with the -F option   awk -F      print substr  0  index  0   3       You can also operate this on a subset of the input lines by specifying a pattern before the action in     Only lines matching the pattern will have the action run   awk  pattern print substr  0  index  0   3       Where pattern can be something such as     abcdef   use regular expression  operates on  0 by default   1    abcdef   operate on a specific field   1    blabla  use string comparison NR  gt  1  use record line number NF  gt  0  use field column number

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You can do it with cut   cut -d     -f 3- input filename  gt  output filename   Explanation    cut  invoke the cut command -d      use a single space as the delimiter  cut uses TAB by default  -f  specify fields to keep 3-  all the fields starting with field 3 input filename  use this file as the input  gt  output filename  write the output to this file    Alternatively  you can do it with awk   awk    1      2     sub             print   input filename  gt  output filename   Explanation    awk  invoke the awk command  1      2      set field 1 and 2 to the empty string sub        clean up the output fields because fields 1  amp  2 will still be delimited by     print  print the modified line input filename  gt  output filename  same as above

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perl   perl -lane  print join      F 2    F    File   awk   awk    1  2    1  File

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Use kscript  kscript  lines split   select -1 -2  print    file

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Thanks for posting the question  I d also like to add the script that helped me   awk     1     print  0    file

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Its pretty straight forward to do it with only shell  while read A B C  do echo   C  done  lt  oldfile  gt newfile

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You can use sed   sed  s                            This looks for lines starting with one-or-more non-blanks  a blank  another set of one-or-more non-blanks and another blank  and deletes the matched material  aka the first two fields   The           is marginally shorter than the equivalent but more explicit       1    notation  and the second might run into issues with GNU sed  though if you use --posix as an option  even GNU sed can t screw it up    OTOH  if the character class to be repeated was more complex  the numbered notation wins for brevity   It is easy to extend this to handle  blank or tab  as separator  or  multiple blanks  or  multiple blanks or tabs    It could also be modified to handle optional leading blanks  or tabs  before the first field  etc   For awk and cut  see Sampson-Chen s answer   There are other ways to write the awk script  but they re not materially better than the answer given   Note that you might need to set the field separator explicitly  -F     in awk if you do not want tabs treated as separators  or you might have multiple blanks between fields   The POSIX standard cut does not support multiple separators between fields  GNU cut has the useful but non-standard -i option to allow for multiple separators between fields   You can also do it in pure shell   while read junk1 junk2 residue do echo   residue  done  lt  in-file  gt  out-file

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awk    1  2     0  0  1  1 1    Input  a b c d   Output  c d

User · Answer

Using awk  and based in some of the options below  using a for loop makes a bit more flexible  sometimes I may want to delete the first 9 columns   if I do an  ls -lrt  for example   so I change the 2 for a 9 and that s it   awk    for i 0 i   lt 2    i      print  0    your file txt

[perl] how to remove the first two columns in a file using shell (awk, sed, whatever)

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