linux cat into columns code example

Example: bash concatenate two columns

# Basic syntax using awk:
awk 'BEGIN {FS="input_delimiter"; OFS="output_delimiter"}; {print $column# "sep" $column#}' input_file

# Where:
#	- The input_delimiter is the delimiter separating columns in 
#		the input_file
#	- The output_delimiter is is the delimiter separating columns in 
#		the output
#	- column# is the column to concatenate (row-wise)
#	- sep is optional separating text between the columns

# Example usage: 
# Say you had a file with fields like the following and want to combine
#	fields 2 and 4 in the output
a,series,of,comma
separated,columns,to,be
joined,together,using,the
second,and,fourth,columns

# Running:
awk 'BEGIN {FS=","; OFS="\t"}; {print $2 "_" $4}' input_file

# Would return:
series_comma
columns_be
together_the
and_columns