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bashgrep
Zach Kirsch
Zach Kirsch

Reputation: 49

How to allow variable tab length when calculating number of characters in a line

I'd like to calculate the number of characters in a line, but allow for the value of a tab character to change. I've been working on a bash script that prints out the lines that have >80 characters (within the given files):

grep -r '.\{81,\}' $args

I guess I'm looking for a way to do something like this:

# pseudocode
TAB_LENGTH = 4
LINE_MAX = 80
if ( (number of non-tab characters) + TAB_LENGTH*(number of tab characters) > LINE_MAX)
    print out the file, line number, and line.
fi

Any hints? (I'm quite new to bash scripting).

Upvotes: 0

Views: 199

Answers (1)

Bartimaeus
Bartimaeus

Reputation: 165

If you want to calculate for the number of characters in a line you would treat tab as a single character ('\t'). The width of a tab is set by the shell that you are using.

so you would just need

if ( (number of characters) > LINE_MAX) print out the file, line number, and line. fi

if you want to have control over fixed widths you can use printf to control the minimum field width for a given string.

printf "|%-5s|" "ABC"

which would have an output like this:

|ABC··|

(the · characters are placeholders for spaces in this example)

A very useful page for this can be found here (the syntax is for c++ but the explanations translate over to bash): http://wpollock.com/CPlus/PrintfRef.htm

Upvotes: 1

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