Simple bash script to split csv file by week number - bash

Question

I'm trying to separate a large pipe-delimited file based on a week number field. The file contains data for a full year thus having 53 weeks. I am hoping to create a loop that does the following:
1) check if week number is less than 10 - if it is paste a '0' in front
2) use grep to send the rows to a file (ie `grep '|01|' bigFile.txt > smallFile.txt` )
3) gzip the smaller file (ie `gzip smallFile.txt`)
4) repeat
Is there a resource that would show how to do this?
EDIT :
Data looks like this:
1|#gmail|1|0|0|0|1|01|com
1|#yahoo|0|1|0|0|0|27|com
The column I care about is the 2nd from the right.
EDIT 2:
Here's the script I'm using but it's not functioning:
for (( i = 1; i <= 12; i++ )); do
#statements
echo 'i :'$i
q=$i
# echo $q
# $q==10
if [[ q -lt 10 ]]; then
#statements
k='0'$q
echo $k
grep '|$k|' 20150226_train.txt > 'weeks_files/week'$k
gzip weeks_files/week $k
fi
if [[ q -gt 9 ]]; then
#statements
echo $q
grep \'|$q|\' 20150226_train.txt > 'weeks_files/week'$q
gzip 'weeks_files/week'$q
fi
done

Answer 1

Very simple in awk ...
awk -F'|' '{ print > ("smallfile-" $(NF-1) ".txt";) }' bigfile.txt
Edit: brackets added for "original-awk".

Answer 2

You're almost there.
#!/bin/bash
for (( i = 1; i <= 12; i++ )); do
#statements
echo 'i :'$i
q=$i
# echo $q
# $q==10
#OLD if [[ q -lt 10 ]]; then
if [[ $q -lt 10 ]]; then
#statements
k='0'$q
echo $k
#OLD grep '|$k|' 20150226_train.txt > 'weeks_files/week'$k
grep "|$k|" 20150226_train.txt > 'weeks_files/week'$k
#OLD gzip weeks_files/week $k
gzip weeks_files/week$k
#OLD fi
#OLD if [[ q -gt 9 ]]; then
elif [[ $q -gt 9 ]] ; then
#statements
echo $q
#OLD grep \'|$q|\' 20150226_train.txt > 'weeks_files/week'$q
grep "|$q|" 20150226_train.txt > 'weeks_files/week'$q
gzip 'weeks_files/week'$q
fi
done
You didn't alway use $ in front of your variable values. You can only get away with using k or q without a $ inside the shell arthimetic substitution feature, ie z=$(( x+k)) or just to operate on a variable like (( k++ )). There are others.
You need to learn the difference between single quoting and dbl-quoting. You need to use dbl-quoting when you want a value substituted for a variable, as in your lines
grep "|$q|" 20150226_train.txt > 'weeks_files/week'$q
and others.
I'm guessing that your use of grep \'|$q|\' 20150226_train.txt was an attempt to get the value of $q.
The way to get comfortable with debugging this sort of situation is to set the shell debugging option with set -x (turn it off with set +x). You'll see each line that is executed with the values substituted for the variables. Advanced debugging requires echo "varof Interset now = $var" (print statements). Also, you can use set -vx (and set +vx) to see each line or block of code before it is executed, and then the -x output will show which lines where acctually executed. For your script, you'd see the whole if ... elfi ...fi block printed, and then just the lines of -x output with values for variables. It can be confusing, even after years of looking at it. ;-)
So you can go thru and remove all lines with the prefix #OLD, and I'm hoping your code will work for you.
IHTH

Answer 3

mkdir -p weeks_files &&
awk -F'|' '
{ file=sprintf("weeks_files/week%2d",$(NF-1)); print > file }
!seen[file]++ { print file }
' 20150226_train.txt |
xargs gzip
If your data is ordered so that all of the rows for a given week number are contiguous you can make it simpler and more efficient:
mkdir -p weeks_files &&
awk -F'|' '
$(NF-1) != prev { file=sprintf("weeks_files/week%2d",$(NF-1)); print file }
{ print > file; prev=$(NF-1) }
' 20150226_train.txt |
xargs gzip

Answer 4

There are certainly a number of approaches - the 'awk' line below will reformat your data. If you take a sequential approach, then:
1) awk to reformat
awk -F '|' '{printf "%s|%s|%s|%s|%s|%s|%s|%02d|%s\n", $1, $2, $3, $4, $5, $6, $7, $8, $9}' SOURCE_FILE > bigFile.txt
2) loop through the weeks, create small file an zip it
for N in {01..53}
do
grep "|${N}|" bigFile.txt > smallFile.${N}.txt
gzip smallFile.${N}.txt
done
3) test script showing reformat step
#!/bin/bash
function show_data {
# Data set w/9 'fields'
# 1| 2 |3|4|5|6|7| 8|9
cat << EOM
1|#gmail|1|0|0|0|1|01|com
1|#gmail|1|0|0|0|1|2|com
1|#gmail|1|0|0|0|1|5|com
1|#yahoo|0|1|0|0|0|27|com
EOM
}
###
function stars {
echo "## $# ##"
}
###
stars "Raw data"
show_data
stars "Modified data"
# 1| 2| 3| 4| 5| 6| 7| 8|9 ##
show_data | awk -F '|' '{printf "%s|%s|%s|%s|%s|%s|%s|%02d|%s\n", $1, $2, $3, $4, $5, $6, $7, $8, $9}'
Sample run:
$ bash test.sh
## Raw data ##
1|#gmail|1|0|0|0|1|01|com
1|#gmail|1|0|0|0|1|2|com
1|#gmail|1|0|0|0|1|5|com
1|#yahoo|0|1|0|0|0|27|com
## Modified data ##
1|#gmail|1|0|0|0|1|01|com
1|#gmail|1|0|0|0|1|02|com
1|#gmail|1|0|0|0|1|05|com
1|#yahoo|0|1|0|0|0|27|com