Trim leading and trailing spaces from a string in awk

Question

I m trying to remove leading and trailing space in 2nd column of the below input txt   Name  Order     Trim  working cat cat1  I have used the below awk to remove leading and trailing space in 2nd column but it is not working  What am I missing   awk -F     2  2  1  input txt   This gives the output as   Name  Order     Trim  working cat cat1  Leading and trailing spaces are not removed

User · Answer

Warning by  Geoff  see my note below  only one of the suggestions in this answer works  though on both columns   I would use sed  sed  s        input txt  This will remove on leading space after the     Output  Name Order Trim working cat cat1  More general might be the following  it will remove possibly multiple spaces and or tabs after the    sed  s     t      g  input txt  It will also work with more than two columns because of the global modifier  g   Floris asked in discussion for a solution that removes trailing and and ending whitespaces in each colum  even the first and last  while not removing white spaces in the middle of a column  sed  s    t       t      g  s     t     g  s    t      g  input txt   EDIT by  Geoff  I ve appended the input file name to this one  and now it only removes all leading  amp  trailing spaces  though from both columns   The other suggestions within this answer don t work  But try   quot    Multiple spaces      and 2 spaces before here  quot     IMO sed is the optimal tool for this job  However  here comes a solution with awk because you ve asked for that  awk -F       printf  quot  s  s n quot    1   2   input txt   Another simple solution that comes in mind to remove all whitespaces is tr -d  cat input txt   tr -d

User · Answer

I just came across this  The correct answer is   awk  BEGIN FS OFS       gsub      space        space           2   1

User · Answer

If it is safe to assume only one set of spaces in column two  which is the original example     awk   print  1 2    tmp input txt  Adding another field  e g  awk   print  1 2 3    tmp input txt will catch two sets of spaces  up to three words in column two   and won t break if there are fewer     If you have an indeterminate  large  number of space delimited words  I d use one of the previous suggestions  otherwise this solution is the easiest you ll find using awk

User · Answer

If you want to trim all spaces  only in lines that have a comma  and use awk  then the following will work for you   awk -F       gsub           0   print    input txt   If you only want to remove spaces in the second column  change the expression to  awk -F       gsub           2   print 1    2    input txt   Note that gsub substitutes the character in    with the second expression  in the variable that is the third parameter - and does so in-place - in other words  when it s done  the  0  or  2  has been modified   Full explanation   -F             use comma as field separator                  so the thing before the first comma is  1  etc                 operate only on lines with a comma                  this means empty lines are skipped  gsub a b c     match the regular expression a  replace it with b                  and do all this with the contents of c print 1    2   print the contents of field 1  a comma  then field 2 input txt      use input txt as the source of lines to process   EDIT I want to point out that  BMW s solution is better  as it actually trims only leading and trailing spaces with two successive gsub commands  Whilst giving credit I will give an explanation of how it works   gsub      t        2      - starting at the beginning     replace all      zero or more  greedy                               consecutive tabs and spaces with an empty string gsub     t         2      - do the same  but now for all space up to the end of string     1                         -   true   Shorthand for  use default action   which is print  0                           - that is  print the entire  modified  line

User · Answer

Simplest solution is probably to use tr    cat -A input  I    Name   IOrder      Trim  working    cat cat1 I      tr -d    blank     lt  input   cat -A Name Order  Trim working  cat cat1

User · Answer

just use a regex as a separator        - for leading spaces       - for trailing spaces for both leading and trailing  awk -F           print  1 quot   quot  2   input txt

User · Answer

remove leading and trailing white space in 2nd column  awk  BEGIN FS OFS      gsub      t        2  gsub     t         2  1  input txt   another way by one gsub   awk  BEGIN FS OFS       gsub      t      t           2  1  infile

User · Answer

The following seems to work   awk -F     blank         2  2 1  OFS     input txt

[shell] Trim leading and trailing spaces from a string in awk

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