How do you use shell commands to show the first and last column in a text file?
I need some help to figure out how to use the sed command to only show the first and last column in a text file Here's what i have so far for column 1
cat logfile | sed 's/\|/ /'|awk '{print $1}'
My poor effort at showing the last column was unsuccessful
cat logfile | sed 's/\|/ /'|awk '{print $1}{print $8}'
However this takes the first column and last column and merges them together in one list. Is there a way to print the first column and last columns clearly with sed and awk commands?
Sample input.
foo|dog|cat|mouse|lion|ox|tiger|bar
It's almost there You'll put the columns next to each other
cat logfile | sed 's/|/ /' | awk '{print $1, $8}'
Also note that you don't need cat
here.
sed 's/|/ /' logfile | awk '{print $1, $8}'
Also note you can tell awk
that the column separators is |
, instead of blanks, so you don't need sed
either.
awk -F '|' '{print $1, $8}' logfile
As per suggestions by Caleb, if you want a solution that still outputs the last field, even if there are not exactly eight, you can use $NF
.
awk -F '|' '{print $1, $NF}' logfile
Also, if you want the output to retain the |
separators, instead of using a space, you can specify the output field separators. Unfortunately, it's a bit more clumsy than just using the -F
flag, but here are three approaches.
You can assign the input and output field separators in
awk
itself, in the BEGIN block.awk 'BEGIN {FS = OFS = "|"} {print $1, $8}' logfile
You can assign these variables when calling
awk
from the command line, via the-v
flag.awk -v 'FS=|' -v 'OFS=|' '{print $1, $8}' logfile
or simply:
awk -F '|' '{print $1 "|" $8}' logfile