Use grep to parse a key from a json file and get the value

Question

Can someone suggest how I can get the value 45 after parsing an example json text as shown below :

....
"test": 12
"job": 45
"task": 11
.....

Please note that I am aware of tools like jq and others but this requires it to be installed.

I am hoping to get this executed using grep, awk or sed command.

Installing jq is not that hard: it's a single binary file (no external dependencies) that can be copied into any directory. — chepner
– chepner, Commented Aug 10, 2016 at 16:44
Why not use a specialized tool like jq for the job, jq is sed forjson — sjsam
– sjsam, Commented Aug 10, 2016 at 16:57

Ed Morton · Accepted Answer · 2016-08-10 18:53:16Z

2

awk -F'[[:space:]]*:[[:space:]]*' '/^[[:space:]]*"job"/{ print $2 }'
sed -n 's/^[[:space:]]*"job"[[:space:]]*:[[:space:]]*//p'

edited Aug 10, 2016 at 18:53

answered Aug 10, 2016 at 16:53

Ed Morton

209k18 gold badges90 silver badges212 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

hek2mgl Over a year ago

It's very unlikely that a key in a json file starts at the begin of the line. While a simple task can indeed be done with grep/sed/awk, I would strongly recommend jq. It's not hard to install it - like chepner mentioned

Ed Morton Over a year ago

The OP already stated he can't/won't install jq and asked for a solution using standard UNIX tools instead. I use plenty of machines where I don't have permission to install any tools, maybe that's the case for the OP too, idk. I also use lots of machines I have to jump on and do something with quickly so I tend to avoid solutions that use non-standard tools for that reason too. I'll add some optional white space at the front in case the OPs real input doesn't follow the format of the input he posted.

hek2mgl Over a year ago

Sure, for a short interactive hack that might be good enough. But for a script or program not. If the OP can't use jq, he can use a scripting language like PHP, Python, Perl or whatever. Something that can process json is almost certainly installed.

Ed Morton Over a year ago

If jq WAS installed then he'd probably have php, pyhon, perl, etc. but if it's not then there's no reason to think any of those others non-standard tools are and if the OP can't install jq then he almost certainly can't install any of the others.

anubhava · Accepted Answer · 2016-08-10 16:21:14Z

2

You can use grep -oP (PCRE):

grep -oP '"job"\s*:\s*\K\d+' file

45

\K is used for reseting the previously matched data.

answered Aug 10, 2016 at 16:21

anubhava

790k67 gold badges603 silver badges671 bronze badges

Comments

sps · Accepted Answer · 2016-08-10 16:56:59Z

0

Using awk, if you just want to print it:

awk -F ':[ \t]*' '/^.*"job"/ {print $2}' filename

Above command matches any line that has "job" at the beginning of a line, and then prints the second column of that line. awk option -F is used to set the column separator as : followed by any number of spaces or tabs.

If you want to store this value in bash variable job_val:

job_val=$(awk -F ':[ \t]*' '/^.*"job"/ {print $2}' filename)

edited Aug 10, 2016 at 16:56

answered Aug 10, 2016 at 16:25

sps

2,7302 gold badges24 silver badges42 bronze badges

Comments

sjsam · Accepted Answer · 2016-08-10 18:31:25Z

0

Use specialized tools like jq for the task :

Had your file looked like

[
{
"test": 12,
"job": 45,
"task": 11
}
]

below stuff would get you home

jq ".[].job" file

Had your file looked like

{
"stuff" :{
.
.
"test": 12,
"job": 45,
"task": 11
.
.
}
}

below

jq ".stuff.job" file

would get you home.

answered Aug 10, 2016 at 18:31

sjsam

22k6 gold badges63 silver badges114 bronze badges

Collectives™ on Stack Overflow

Use grep to parse a key from a json file and get the value

4 Answers 4

4 Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

4 Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related