AWK in single line pass multiple commands - bash

Question

I would like to combine the following multiple awk commands into a single awk program:
awk -F 'FS' '{ $1 = ($1 == "}" ? "" : $1) } 1' sorce > destfil
awk -F 'FS' '{ $3 = ($3 == "]" ? "" : $3) } 1' sorce > destfil
awk -F 'FS' '{ $5 = ($5 == "}" ? "}," : $5) } 1' sorce > destfil
I have tried to accomplish this using && but the result is not what I expected.
awk -F 'FS' '{ $1 = ($1 == "}" ? "" : $1) && $3 = ($3 == "]" ? "" : $3) && $5 = ($5 == "}" ? "}," : $5) } 1' sorce > destfil
The output seems to have various ZERO's in it.
Question:
How can I merge these lines?
What is the origin of the ZEROS?
Thank you!
#RavinderSingh13, as I tried your code, sample input file and output file as per below
[user#restt]$ tail source
{
}
]
}
{
" e t
{
}
]
}
[user#test]$ awk -F 'FS' '{$1=($1=="}"?"":$1); $3=($3=="]" ? "" : $3) ; $5=($5=="}" ? "}," :$5);} 1' source > target
[user#test]$ tail target
{
}
]
}
{
" e t
{
}
]
}
I think the issue is related to field separator -F 'FS' or I was not sure.
#kvantour, Below I have given my sample input file & command what I am running & what output I am getting & what I require.
Source file content :
{
"metadata": [
{
sample content line 1
sample content line n
}
]
}
{
"metadata": [
{
sample content line 1
sample content line n
}
]
}
{
"metadata": [
{
sample content line 1
sample content line n
}
]
}
{
"metadata": [
{
sample content line 1
sample content line n
}
]
}
A command I am running
$ awk '($1=="}"){$1="First Column"}
($3=="]"){$3="third Column"}
($5=="}"){$5="Fifth Column"}
{$1=$1}1' sample.json > out
Output I am getting :
[root#centos-src ~]# cat out
{
"metadata": [
{
sample content line 1
sample content line n
First Column
]
First Column
{
"metadata": [
{
sample content line 1
sample content line n
First Column
]
First Column
{
"metadata": [
{
sample content line 1
sample content line n
First Column
]
First Column
{
"metadata": [
{
sample content line 1
sample content line n
First Column
]
First Column
but I am expecting output is:
{
"metadata": [
{
sample content line 1
sample content line n
Fifth Column
third Column
First Column
{
"metadata": [
{
sample content line 1
sample content line n
Fifth Column
third Column
First Column
{
"metadata": [
{
sample content line 1
sample content line n
Fifth Column
third Column
First Column
{
"metadata": [
{
sample content line 1
sample content line n
Fifth Column
third Column
First Column

Answer 1

In a nice awk structure, one would write:
awk -F 'FS' '($1=="}"){$1=""}
($3=="]"){$3=""}
($5=="}"){$5="},"}
{$1=$1}1' <file>
The reason I add $1=$1 to the list, is to reprocess $0 for the correct OFS in case none of the above conditions was satisfied. If you don't do this, you will have lines printed with FS as field separator and others with OFS.
So why are you getting a bunch of zeros?
Let's look at your one-liner:
$1 = ($1 == "}" ? "" : $1) && $3 = ($3 == "]" ? "" : $3) && $5 = ($5 == "}" ? "}," : $5)
And simplify it by assuming that the ternary operators between brackets return a variable. So we can rewrite it as:
$1 = var1 && $3 = var3 && $5 = var5
Taking into account that:
expr1 && expr2 has a higher precedence than value = expr.
lvalue = expr returns the value of expr
We can see that awk interprets this as
$1 = var1 && ($3 = (var3 && ($5 = var5) ) )
So the result will be:
$5 = var5
$3 = var3 && $5 equalling var3 && var5
$1 = var1 && $3 equalling var1 && var5
This is visible in the following example:
$ echo "a b c d e f" | awk '{ $1="p" && $3 = "q" && $5 = "r"}1'
1 b 1 d rf
Finally, in awk an empty string and a numeric zero has the logical value false and anything else true. So since two of your original ternary operators can return empty strings, they will ensure that the logical AND will return false, which is equivalent to the number ZERO. Hence $1 and $3 will be both matched with ZERO if the original $3 equals ]
Update (after receiving [mcve])
What you try to achieve is not that easy. First off, it seems you assume that the column number implies the character number in the line. This is sadly not the case. Awk, in default mode, assumes that field $n is the nth word in the line where a word is a sequence of characters not containing any blank. So in the following text,
}
]
}
all characters are actually referenced by $1.
Under the assumption that your JSON file is perfectly indented, one could use the following:
awk '/^} *$/{$0="First Column"}
/^ ] *$/{$0=" Thrid Column"}
/^ } *$/{$0=" Fifth Column"}
{print $0}' <file>
However, if your JSON file is not indented uniformly, things become rather messy. The easiest would be to parse the file first with jq as
jq . <json-file> | awk ...

Answer 2

Is this what you're trying to do (given your source input file)?
$ awk '
BEGIN{ FS="[ ]"; map[1,"}"]=map[3,"]"]=map[5,"}"]="" }
{ for (i=1;i<=NF;i++) $i=((i,$i) in map ? map[i,$i] : $i); print }
' file
{
{
" e t
{

Answer 3

Usage ; to separate statements:
awk ... '{ $1 = ($1 == "}" ? "" : $1); $3 = ($3 == "]" ? "" : $3); $5 = ($5 == "}" ? "}," : $5); } 1' ...

Answer 4

Since you haven't shown your sample Input_file so couldn't test it, could you please try following.
awk -F 'FS' '{$1=($1=="}"?"":$1);$3=($3=="]"?"":$3);$5=($5=="}"?"":$5);} 1' sorce > destfil