CODEWITHSUNDEEP
bashcsvawk
onur
onur

Reputation: 6365

How can I update lines of file with bash?

I have a small script for disk usage logging, like this:

#!/bin/bash
date=$(date +"%d.%m.%Y")
while read -r filesystem;
do
filesys=${filesystem}

df -P | tr -d "%" | awk '$6=="'"$filesys"'" {print"'"$date"'"",",$6","$5}' >> /root/disk.csv

done < "/root/disklist"

/root/disklist:

/
/dev/mapper/map1

/root/disk.csv:

18.05.2015, /,18
18.05.2015, /dev/mapper/map1,1

When I run this script, print to new line of disk.csv. I need to see actual data, so when I run this script I need to update to same line about same date(not insert).

Not like this:

Run - 18.05.2015 13:00

18.05.2015, /,18
18.05.2015, /dev/mapper/map1,1

Run - 18.05.2015 15:00

18.05.2015, /,18
18.05.2015, /dev/mapper/map1,1
18.05.2015, /,19
18.05.2015, /dev/mapper/map1,5

When run this script, I need to change old line(if date same). How can I do this?

Upvotes: 3

Views: 99

Answers (2)

F. Hauri - Give Up GitHub
F. Hauri - Give Up GitHub

Reputation: 70792

Care: you run df -P without argument, (will generate full stat of all your disks) as many time, you had lines in your /root/disklist.

So there is my purpose (using recent bash):

disklist=(
    /home
    /usr
    /var
)
[ -f "/root/disklist" ] && disklist=($(</root/disklist))

file="/root/disk.csv"

printf -v myDate "%(%d.%m.%Y)T" -1

sed -e "/^$myDate,/d" $file >$file.tmp
df -P "${disklist[@]}" |
    sed -ne 's/^.* \([0-9]\+\)% \(.*\)$/'$myDate', \2, \1/p' >>$file.tmp
read osize < <(stat -c%s $file)
read nsize < <(stat -c%s $file.tmp)
((nsize+=${#disklist[@]}*2))  # So length of % field could become smaller
[ $nsize -ge $osize ] && mv $file.tmp $file || rm -v $file.tmp >&2

The sed -e "/^$myDate,/d" -i $file will inline edit $file to drop all lines which begin by 18.05.2015,, before appending reformated output of df -P.

Upvotes: 4

Ed Morton
Ed Morton

Reputation: 203512

It's not completely clear what you want but maybe this will help:

#!/bin/bash
df -P | awk -v date="$(date +"%d.%m.%Y")" -v OFS=',' '
NR==FNR{disk[$1 OFS $2]=$3; next}
{disk[date OFS $6]=$5+0}
END {for (key in disk) print key, disk[key]}
' FS=',' /root/disk.csv FS=' ' - > tmp && mv tmp /root/disk.csv

Upvotes: 3

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