Deleting columns from a file with awk or from command line on linux

Question

How can I delete some columns from a tab separated fields file with awk?

c1 c2 c3 ..... c60

For example, delete columns be

Answer 1

You can loop over all columns and filter out the ones you don't want:

awk '{for (i=1; i<=NF; i++) if (i<3 || i>29) printf $i " "; print""}' input.txt

where the NF gives you the total number of fields in a record.
For each column that meets the condition we print the column followed by a space " ".

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EDIT: updated after remark from johnny:

awk -F 'FS' 'BEGIN{FS="\t"}{for (i=1; i<=NF-1; i++) if(i<3 || i>5) {printf $i FS};{print $NF}}' input.txt

this is improved in 2 ways:

• keeps the original separators
• does not append a separator at the end