[sed] delete a column with awk or sed

With GNU awk for inplace editing, \s/\S, and gensub() to delete

1) the FIRST field:

awk -i inplace '{sub(/^\S+\s*/,"")}1' file

or

awk -i inplace '{$0=gensub(/^\S+\s*/,"",1)}1' file

2) the LAST field:

awk -i inplace '{sub(/\s*\S+$/,"")}1' file

or

awk -i inplace '{$0=gensub(/\s*\S+$/,"",1)}1' file

3) the Nth field where N=3:

awk -i inplace '{$0=gensub(/\s*\S+/,"",3)}1' file

Without GNU awk you need a match()+substr() combo or multiple sub()s + vars to remove a middle field. See also Print all but the first three columns.