NAME              MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda                 8:0    0 931.5G  0 disk
├─sda1              8:1    0   953M  0 part /boot
├─sda2              8:2    0  29.8G  0 part [SWAP]
└─sda3              8:3    0 900.8G  0 part
  ├─vgmain-lvroot 254:0    0 621.4G  0 lvm  /
  ├─vgmain-lvmail 254:1    0  93.1G  0 lvm  /var/vmail
  ├─vgmain-lvhome 254:2    0  93.1G  0 lvm  /home
  ├─vgmain-lvtmp  254:3    0  18.6G  0 lvm  /tmp
  └─vgmain-lvvar  254:4    0  74.5G  0 lvm  /var
sdb                 8:16   0 931.5G  0 disk

[
    {
        "bytes": 276697,
        "checked": false
    },
    {
        "bytes": 276697,
        "checked": false
    }
]

cat file.json | jq '.[] | join(",")'

"276697,false"
"276697,false"

"bytes,checked"
"276697,false"
"276697,false"

cat file.json | jq '.[] | keys, .[] | join(",")'

"bytes,checked"
jq: error (at :64): Cannot iterate over null (null)

$ sum_sofar=0; for file in $(for i in $(seq 1 4); do echo page_$i.pnm; done | xargs echo); do sum_sofar=$((sum_sofar + $(stat -c%s "$file"))); done; echo "The sum of the sizes of the PNM files is $sum_sofar bytes."
The sum of the sizes of the PNM files is 415300162 bytes.
$ convert $(for i in $(seq 1 4); do echo page_$i.pnm; done | xargs echo) -compress Zip -quality 100 -density 1200 tmp_output_document.convert.pdf && pdftk tmp_output_document.convert.pdf update_info  Producer:        https://imagemagick.org 
> CreationDate:    …
> ModDate:         …
16,17c16,17
 File size:       254364579 bytes
> Optimized:       no