mjhjmtu

I want to insert a new line before the last occurrence of brace. My text file looks like that

 "accounts": 
 "0x0000000000000000000000000000000000000008": "builtin": "name": "alt_bn128_pairing", "activate_at": "0x0", "pricing": "alt_bn128_pairing": "base": 100000, "pair": 80000 ,
 "0x00Ea169ce7e0992960D3BdE6F5D539C955316432": "balance": "1606938044258990275541962092341162602522202993782792835301376" 
 

So what I want to do is adding a new account through sed script.

Please note that the new account will be specified with a variable, something like:

"$ACCOUNT_ADDR": "balance": "1606938044258990275541962092341162602522202993782792835301376" 

sed is the wrong tool for this job. One of the right tools is jq.

% cat wibble.json

"accounts": 
 "0x0000000000000000000000000000000000000008": "builtin": "name": "alt_bn128_pairing", "activate_at": "0x0", "pricing": "alt_bn128_pairing": "base": 100000, "pair": 80000 ,
 "0x00Ea169ce7e0992960D3BdE6F5D539C955316432": "balance": "1606938044258990275541962092341162602522202993782792835301376" 


% ACCOUNT_ADDR="0xdeadbeeffeefdface0badd00dcacad0d0eeeeeeee"
% jq '."accounts"."'"$ACCOUNT_ADDR"'"."balance"="42"' wibble.json

 "accounts": 
 "0x0000000000000000000000000000000000000008": 
 "builtin": 
 "name": "alt_bn128_pairing",
 "activate_at": "0x0",
 "pricing": 
 "alt_bn128_pairing": 
 "base": 100000,
 "pair": 80000
 
 
 
 ,
 "0x00Ea169ce7e0992960D3BdE6F5D539C955316432": 
 "balance": "1606938044258990275541962092341162602522202993782792835301376"
 ,
 "0xdeadbeeffeefdface0badd00dcacad0d0eeeeeeee": 
 "balance": "42"
 
 

%

It also caught the fact that you had a key+value pair with no enclosing object. ☺

You could add a line after the occurence of "accounts",

sed "/accounts/ a
 "$ACCOUNT_ADDR": "balance": "1606938044258990275541962092341162602522202993782792835301376i" 
" file

(The " are escaped, to insert variable)

sed "s/^ }$/ "$ACCOUNT_ADDR": "balance": "1606938044258990275541962092341162602522202993782792835301376i" n }/g" file

Will replace your } line and print two lines.

Run sed -i ... for changing the file, in cycle:

$ cat file
"accounts": 
 "0x0000000000000000000000000000000000000008": "builtin": "name": "alt_bn128_pairing", "activate_at": "0x0", "pricing": "alt_bn128_pairing": "base": 100000, "pair": 80000 ,
 "0x00Ea169ce7e0992960D3BdE6F5D539C955316432": "balance": "1606938044258990275541962092341162602522202993782792835301376" 
 

$ cat script.sh
#!/bin/bash

for i in $(seq 1 5); do
 ACCOUNT_ADDR="account_"$i
 sed -i "/accounts/ a
 "$ACCOUNT_ADDR": "balance": "1606938044258990275541962092341162602522202993782792835301376i" 
 " file
done

$ ./script.sh
$ cat file
"accounts": 
"account_5": "balance": "1606938044258990275541962092341162602522202993782792835301376i" 
"account_4": "balance": "1606938044258990275541962092341162602522202993782792835301376i" 
"account_3": "balance": "1606938044258990275541962092341162602522202993782792835301376i" 
"account_2": "balance": "1606938044258990275541962092341162602522202993782792835301376i" 
"account_1": "balance": "1606938044258990275541962092341162602522202993782792835301376i" 
 "0x0000000000000000000000000000000000000008": "builtin": "name": "alt_bn128_pairing", "activate_at": "0x0", "pricing": "alt_bn128_pairing": "base": 100000, "pair": 80000 ,
 "0x00Ea169ce7e0992960D3BdE6F5D539C955316432": "balance": "1606938044258990275541962092341162602522202993782792835301376" 
 

Every now and and then I like a sed challenge: using ACCOUNT_ADDR=1234:

sed -n -e '
 x
 $ i
"'"$ACCOUNT_ADDR"'": "balance":0,
 2,$ p
 $ x; p 
' file

 "accounts": 
 "0x0000000000000000000000000000000000000008": "builtin": "name": "alt_bn128_pairing", "activate_at": "0x0", "pricing": "alt_bn128_pairing": "base": 100000, "pair": 80000 ,
"1234": "balance":0,
 "0x00Ea169ce7e0992960D3BdE6F5D539C955316432": "balance": "1606938044258990275541962092341162602522202993782792835301376" 
 

This uses the x to stash the current line into the hold space to become the "previous" line in the next cycle.

As mentioned elsewhere, use sed -i to save the edits in-place

You can get the same result by reversing the file and using a simpler sed command:

temp=$(mktemp)
tac file | sed '2a
"'"$ACCOUNT_ADDR"'": "balance":0,
' | tac > "$temp" && mv "$temp" file