I have the following lines:
field1 1-23_4_5 field3
field1 2-40_5_7 field3
field1 3-43_7_9 field3
.
.
.
I would like to modify the second field so that
1-23_4_5 becomes 1-23
I am thinking the combination of awk and cut would do the trick. Is there a simple way to go about this?
Thank you so much for your help in advance.
Through awk,
$ awk 'sub(/_[^_]*_[^_]*$/,"",$2)1' file
field1 1-23 field3
field1 2-40 field3
field1 3-43 field3
Through sed,
$ sed 's/^\([^ ]\+\ *[^_]\+\)[^ ]\+/\1/g' file
field1 1-23 field3
field1 2-40 field3
field1 3-43 field3
Here is one awk version:
awk '{split($2,a,"_");$2=a[1]}1' file
field1 1-23 field3
field1 2-40 field3
field1 3-43 field3
Divide field 2 by _ and use only first part.
PS it changes the formatting. (normal with awk)
You can do this quite easily with a simple bash script using read and substring extraction:
#!/bin/bash
## validate input file
[ -r "$1" ] || { printf "Error: insufficient input. Usage %s <filename>\n"; exit 1; }
## read and extract substring of field2
while read -r f1 f2 f3 || [ -n "$f3" ]; do
printf "%s %s %s\n" "$f1" "${f2%%_*}" "$f3";
done < "$1"
test file:
$ cat dat/field.txt
field1 1-23_4_5 field3
field1 2-40_5_7 field3
field1 3-43_7_9 field3
output:
$ bash fields.sh dat/field.txt
field1 1-23 field3
field1 2-40 field3
field1 3-43 field3
