Add timestamp for each line on the df output command? - linux

Question

I would like to add the date for each line of the df output.
I tried:
df -m | awk '{print `date +%Y-%m`";"$1";"$2";"$3 }'
... but it doesn't work.
How can I add the date?

Answer 1

Here is an alternative:
df -m | awk '{print strftime("%Y-%m"), $0}'
And here is the output from the command above:
$ df -m | awk '{print strftime("%Y-%m"), $0}'
2019-10 Filesystem 1M-blocks Used Available Use% Mounted on
2019-10 devtmpfs 9852 0 9852 0% /dev
2019-10 tmpfs 9871 132 9740 2% /dev/shm
2019-10 tmpfs 9871 2 9869 1% /run
2019-10 /dev/mapper/fedora_canvas-root 50141 14731 32834 31% /
2019-10 tmpfs 9871 1 9871 1% /tmp
2019-10 /dev/sda5 976 243 667 27% /boot
2019-10 /dev/mapper/fedora_canvas-home 1277155 217435 994777 18% /home
2019-10 tmpfs 1975 63 1912 4% /run/user/1000
$
And here is an alternative version, printing just the 3 columns you wanted on the OP:
df -m | awk '{print strftime("%Y-%m"), $1, $2, $3}' | column -t
And the corresponding output:
$ df -m | awk '{print strftime("%Y-%m"), $1, $2, $3}' | column -t
2019-10 Filesystem 1M-blocks Used
2019-10 devtmpfs 9852 0
2019-10 tmpfs 9871 132
2019-10 tmpfs 9871 2
2019-10 /dev/mapper/fedora_canvas-root 50141 14731
2019-10 tmpfs 9871 1
2019-10 /dev/sda5 976 243
2019-10 /dev/mapper/fedora_canvas-home 1277155 217435
2019-10 tmpfs 1975 63
$

Answer 2

You may use this way:
df -m | awk -v dt=$(date "+%Y-%m") '{print dt "::", $0}'
We use -v dt=$(date "+%Y-%m") to execute date command in shell and pass it to awk in an argument dt.
If you want only first 3 columns from df command output then use:
df -m | awk -v dt=$(date "+%Y-%m") '{print dt, $1, $2, $3}'

Answer 3

A Perl solution.
df -m | perl -MPOSIX=strftime -alpe '$_ = strftime("%Y-%M ", localtime) . "#F[0..2]"'
Command line options:
-M : Load thestrftime() function from the POSIX module
-a : Autosplit the input records on whitespace into #F
-l : Remove newlines from input and add them to output
-p : Put each input record into $_, execute code and then print $_
-e : Run this code for each input record
The code updates $_ by concatenating the date (strftime("%Y-%M ", localtime)) with the first three columns (#F[0 .. 2]) of the input record.