Extracting JSON variable using bash - linux

I need to extract the variable from a JSON encoded file and assign it to a variable in Bash.
excerpt...from file.json
"VariableA": "VariableA data",
"VariableB": [
"VariableB1",
"VariableB2",
"VariableB3",
"VariableB3"
],
I've gotten somewhere with this
variableA=$(fgrep -m 1 "VariableA" file.json )
but it returns the whole line. I just want the data
For the VariableB I need to replace the list with comma separated values.
I've looked at awk, sed, grep, regexpressions and really given the learning curve...need to know which one to use, or a better solution.
Thanks for your suggestions...but this is perfect
git://github.com/kristopolous/TickTick.git

You are better off using a JSON parser. There are many listed at http://json.org/ including two for the BASH shell.
http://kmkeen.com/jshon/
https://github.com/dominictarr/JSON.sh

There is powerful command-line JSON tool jq.
Extracting single value is easy:
variableA=$(jq .VariableA file.json)
For comma separated array contents try this
variableB=$(jq '.VariableB | #csv' file.json)
or
variableB=$(jq '.VariableB | .[]' file.json | tr '\n' ',' | head -c-1)

If you're open to using Perl they have a 'open()' function that will pipe a file with the json function 'to_json'. And if you want to extract json you can use the 'from_json' function. You can check it out here:
http://search.cpan.org/~rjbs/perl-5.16.0/lib/open.pm
http://metacpan.org/pod/JSON#to_json
http://metacpan.org/pod/JSON#from_json ( you might also try using decode json as well)

Related

how can i make the lines variable in a file?

I am using a unix based program. I want to automate the code so as not to copy and paste data one by one. For this, I need to define line-by-line data in a file as a variable for the code
The program converts xyz coordinates to local coordinates. How can I run the coordinates in the xyz_coordinates file I created, one by one, in the code below? In the program I use, the conversion code works like this:
echo 4208830.039709186 2334850.551667509 4171267.377406844 -6.753E-01 4.493E-01 2.849E-01 | xyz2env.py
and this is the file i am trying to run:
2679689.926729193 -727950.9964290063 5722789.538975053 7.873E-02 3.466E-01 6.410E-01
2679689.927123377 -727950.9971557076 5722789.540522 7.912E-02 3.458E-01 6.425E-01
2679689.930567728 -727950.9979971027 5722789.550832021 8.257E-02 3.450E-01 6.528E-01
2679689.931029495 -727950.9992263148 5722789.549927638 8.303E-02 3.438E-01 6.519E-01
2679689.929031829 -727950.9981009626 5722789.546359798 8.103E-02 3.449E-01 6.484E-01
........
and it goes on like this. Also, there are spaces between the lines. Will this be a problem?
You can use xargs to invoke the command for a specific number of arguments (6 in your case) and have the advantage of skipping empty lines automatically
< file.txt xargs -n 6 xyz2env.py

Split single record into Multiple records in Unix shell Script

I have record
Example:
EMP_ID|EMP_NAME|AGE|SALARAy
123456|XXXXXXXXX|30|10000000
Is there a way i can split the record into multiple records. Example output should be like
EMP_ID|Attributes
123456|XXXXXXX
123456|30
123456|10000000
I want to split the same record into multiple records. Here Employee id is my unique column and remaining 3 columns i want to run in a loop and create 3 records. Like EMP_ID|EMP_NAME , EMP_ID|AGE , EMP_ID|SALARY. I may have some more columns as well but for sample i have provided 3 columns along with Employee id.
Please help me with any suggestion.
With bash:
record='123456|XXXXXXXXX|30|10000000'
IFS='|' read -ra fields <<<"$record"
for ((i=1; i < "${#fields[#]}"; i++)); do
printf "%s|%s\n" "${fields[0]}" "${fields[i]}"
done
123456|XXXXXXXXX
123456|30
123456|10000000
For the whole file:
{
IFS= read -r header
while IFS='|' read -ra fields; do
for ((i=1; i < "${#fields[#]}"; i++)); do
printf "%s|%s\n" "${fields[0]}" "${fields[i]}"
done
done
} < filename
Record of lines with fields separated by a special delimiter character such as | can be manipulated by basic Unix command line tools such as awk. For example with your input records in file records.txt:
awk -F\| 'NR>1{for(i=2;i<=NF;i++){print $1"|"$(i)}}' records.txt
I recommend to read a awk tutorial and play around with it. Related command line tools worth to learn include grep, sort, wc, uniq, head, tail, and cut. If you regularly do data processing of delimiter-separated files, you will likely need them on a daily basis. As soon as your data structuring format gets more complex (e.g. CSV format with possibility to also use the delimiter character in field values) you need more specific tools, for instance see this question on CSV tools or jq for processing JSON. Still knowledge of basic Unix command line tools will save you a lot of time.

Filtering a Block

I have multiple blocks of the below pattern
<APPLIANCE>
<ID>12233</ID>
<UUID>xxxx-xxxx-xxxx-xxxx-xxxxxxx</UUID>
<NAME>xxxxxxx</NAME>
<STATUS>Offline</STATUS>
</APPLIANCE>
<APPLIANCE>
<ID>12234</ID>
<UUID>xxxx-xxxx-xxxx-xxxx-xxxxxxx</UUID>
<NAME>yyyyy</NAME>
<STATUS>Offline</STATUS>
</APPLIANCE>
I want to extract a block with Particular ID and Particular Name.
The output should display
For example :-
<ID>12234</ID>
<NAME>yyyyy</NAME>
I wanted to do using grep, sed, awk
Thanks.
This sed should work for you:
sed -n '/<ID>12234/,/<NAME>/{//p}' file
But you'd better use an xml parser as xmllint or xmlstarlet to parse valid xml files.

Filtering CSV File using AWK

I'm working on CSV file
This my csv file
Command used for filtering awk -F"," '{print $14}' out_file.csv > test1.csv
This is an example of my data looks like i have around 43 Row and 12,000 column
i planed to separate the single Row using awk command but i cant able to separate the row 3 alone (disease).
i use the following command to get my output
awk -F"," '{print $3}' out_file.csv > test1.csv
This is my file:
gender|gene_name |disease |1000g_oct2014|Polyphen |SNAP
male |RB1,GTF2A1L|cancer,diabetes |0.1 |0.46 |0.1
male |NONE,LOC441|diabetes |0.003 |0.52 |0.6
male |TBC1D1 |diabetes |0.940 |1 |0.9
male |BCOR |cancer |0 |0.31 |0.2
male |TP53 |diabetes |0 |0.54 |0.4
note "|" i did not use this a delimiter. it for show the row in an order my details looks exactly like this in the spreed sheet:
But i'm getting the output following way
Disease
GTF2A1L
LOC441
TBC1D1
BCOR
TP53
While opening in Spread Sheet i can get the results in the proper manner but when i uses awk the , in-between the row 2 is also been taken. i dont know why
can any one help me with this.
The root of your problem is - you have comma separated values with embedded commas.
That makes life more difficult. I would suggest the approach is to use a csv parser.
I quite like perl and Text::CSV:
#!/usr/bin/env perl
use strict;
use warnings;
use Text::CSV;
open ( my $data, '<', 'data_file.csv' ) or die $!;
my $csv = Text::CSV -> new ( { binary => 1, sep_char => ',', eol => "\n" } );
while ( my $row = $csv -> getline ( $data ) ) {
print $row -> [2],"\n";
}
Of course, I can't tell for sure if that actually works, because the data you've linked on your google drive doesn't actually match the question you've asked. (note - perl starts arrays at zero, so [3] is actually the 4th field)
But it should do the trick - Text::CSV handles quoted comma fields nicely.
Unfortunately the link you provided ("This is my file") points to two files, neither of which (at the time of this writing) seems to correspond with the sample you gave. However, if your file really is a CSV file with commas used both for separating fields and embedded within fields, then the advice given elsewhere to use a CSV-aware tool is very sound. (I would recommend considering a command-line program that can convert CSV to TSV so the entire *nix tool chain remains at your disposal.)
Your sample output and attendant comments suggest you may already have a way to convert it to a pipe-delimited or tab-delimited file. If so, then awk can be used quite effectively. (If you have a choice, then I'd suggest tabs, since then programs such as cut are especially easy to use.)
The general idea, then, is to use awk with "|" (or tab) as the primary separator (awk -F"|" or awk -F\\t), and to use awk's split function to parse the contents of each top-level field.
At last this is what i did for getting my answers in a simple way thanks to #peak i found the solution
1st i used the
CSV filter which is an python module used for filtering the csv file.
i changed my delimiters using csvfilter using the following command
csvfilter input_file.csv --out-delimiter="|" > out_file.csv
This command used to change the delimiter ',' into '|'
now i used the awk command to sort and filter
awk -F"|" 'FNR == 1 {print} {if ($14 < 0.01) print }' out_file.csv > filtered_file.csv
Thanks for your help.

Bash script key/value pair regardless of bash version

I am writing a curl bash script to test webservices. I will have file_1 which would contain the URL paths
/path/to/url/1/{dynamic_path}.xml
/path/to/url/2/list.xml?{query_param}
Since the values in between {} is dynamic, I am creating a separate file, which will have values for these params. the input would be in key-value pair i.e.,
dynamic_path=123
query_param=shipment
By combining two files, the input should become
/path/to/url/1/123.xml
/path/to/url/2/list.xml?shipment
This is the background of my problem. Now my questions
I am doing it in bash script, and the approach I am using is first reading the file with parameters and parse it based on '=' and store it in key/value pair. so it will be easy to replace i.e., for each url I will find the substring between {} and whatever the text it comes with, I will use it as the key to fetch the value from the array
My approach sounds okay (at least to me) BUT, I just realized that
declare -A input_map is only supported in bashscript higher than 4.0. Now, I am not 100% sure what would be the target environment for my script, since it could run in multiple department.
Is there anything better you could suggest ? Any other approach ? Any other design ?
P.S:
This is the first time i am working on bash script.
Here's a risky way to do it: Assuming the values are in a file named "values"
. values
eval "$( sed 's/^/echo "/; s/{/${/; s/$/"/' file_1 )"
Basically, stick a dollar sign in front of the braces and transform each line into an echo statement.
More effort, with awk:
awk '
NR==FNR {split($0, a, /=/); v[a[1]]=a[2]; next}
(i=index($0, "{")) && (j=index($0,"}")) {
key=substr($0,i+1, j-i-1)
print substr($0, 1, i-1) v[key] substr($0, j+1)
}
' values file_1
There are many ways to do this. You seem to think of putting all inputs in a hashmap, and then iterate over that hashmap. In shell scripting it's more common and practical to process things as a stream using pipelines.
For example, your inputs could be in a csv file:
123,shipment
345,order
Then you could process this file like this:
while IFS=, read path param; do
sed -e "s/{dynamic_path}/$path/" -e "s/{query_param}/$param/" file_1
done < input.csv
The output will be:
/path/to/url/1/123.xml
/path/to/url/2/list.xml?shipment
/path/to/url/1/345.xml
/path/to/url/2/list.xml?order
But this is just an example, there can be so many other ways.
You should definitely start by writing a proof of concept and test it on your deployment server. This example should work in old versions of bash too.

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