I have a .tsv file (values separated by tabs) with four values. So each line should have only three tabs and some text around each tab like this:

value   value2  value3  value4

But it looks that some lines are broken (there is more than three tabs). I need to find out these lines.

I came up with following grep pattern.

grep -v "^[^\t]+\t[^\t]+\t[^\t]+\t[^\t]+$"

My thinking:

• first ^ matches the beggining
• [^\t]+ matches more than one "no tab character"
• \t matches single tab character
• $ matches end

And than I just put it into right order with correct number of times. That should match correct lines. So I reverted it by -v option to get the wrong lines.

But with the -v option it matches any line in the file and also some random text I tried that don't have any tabs inside.

What is my mistake please?

I have a .tsv file (values separated by tabs) with four values. So each line should have only three tabs and some text around each tab like this:

value   value2  value3  value4

But it looks that some lines are broken (there is more than three tabs). I need to find out these lines.

I came up with following grep pattern.

grep -v "^[^\t]+\t[^\t]+\t[^\t]+\t[^\t]+$"

My thinking:

• first ^ matches the beggining
• [^\t]+ matches more than one "no tab character"
• \t matches single tab character
• $ matches end

And than I just put it into right order with correct number of times. That should match correct lines. So I reverted it by -v option to get the wrong lines.

But with the -v option it matches any line in the file and also some random text I tried that don't have any tabs inside.

What is my mistake please?

EDIT: I am using debian and bash.

I have a .tsv file (values separated by tabs) with four values. So each line should have only three tabs and some text around each tab like this:

value   value2  value3  value4

But it looks that some lines are broken (there is more than three tabs).

I came up with following grep pattern.

grep -v "^[^\t]+\t[^\t]+\t[^\t]+\t[^\t]+$"

My thinking:

• first ^ matches the beggining
• [^\t]+ matches more than one "no tab character"
• \t matches single tab character
• $ matches end

And than I just put it into right order with correct number of times. That should match correct lines. So I reverted it by -v option to get the wrong lines.

But with the -v option it matches any line in the file and also some random text I tried that don't have any tabs inside.

What is my mistake please?

I have a .tsv file (values separated by tabs) with four values. So each line should have only three tabs and some text around each tab like this:

value   value2  value3  value4

But it looks that some lines are broken (there is more than three tabs). I need to find out these lines.

I came up with following grep pattern.

grep -v "^[^\t]+\t[^\t]+\t[^\t]+\t[^\t]+$"

My thinking:

• first ^ matches the beggining
• [^\t]+ matches more than one "no tab character"
• \t matches single tab character
• $ matches end

And than I just put it into right order with correct number of times. That should match correct lines. So I reverted it by -v option to get the wrong lines.

But with the -v option it matches any line in the file and also some random text I tried that don't have any tabs inside.

What is my mistake please?