Ubuntu – align columns right

bashcommand linetext;

For the command shell, is there a common program like column that has an option to align specific or all columns to the right, if not also detect numeric fields and do so automatically for those?

Otherwise what might be the most concise way with text-processing commands?

Example space-delimited input already piped through | column -t:

TVN         20120419  10.08  10.08  9.15   9.6    1630000  9.17    20120419  4.6      83.88   7376600    -0.21858
INTEGERPL   20120419  143.1  148.9  140.3  142.5  2910     138.53  20120405  4.32503  5.55    1642500    1.26158
JSW         20120419  93.55  94.4   91.25  92.7   116000   90.07   20120329  3.86997  8.54    13155770   1.29315
KERNEL      20120419  73.7   74.9   72.9   74.1   56200    71.8    20120404  3.48432  10.71   2819790    1.50892
EUROCASH    20120419  39.49  41.99  39.01  40.73  812000   38.05   20120328  4.85095  20.21   5280548    2.46091
PEKAO       20120419  145.9  147.8  144.0  145.5  292000   140.2   20120404  3.70615  5.48    68858748   2.63889
PKNORLEN    20120419  38.0   38.5   37.25  37.35  1230000  36.26   20120329  4.15476  21.21   104607200  2.65772

Notice readability issues esp. where differences between records are by several magnitudes (like 2nd last column).
Incidentally, formatting prices to always show N decimal places is a problem of its own. But I've used awk's OFMT="%.4f" for that.

Best Answer

Alignment and numeric field detection can be achieved by the following simple awk program.

{
    width=10;
    separator="|";

    for (i=1; i<=NF; i++) {
        if (match($i, /[-+]*[0-9]+[\.]*[0-9]*/)) {
            printf("%"width"s", $i);
        }
        else { 
            printf("%-"width"s", $i);
        }
        if (i == NF) printf("\n");
        else printf("%s", separator);
    }
}

Save it as column.awk.

To test how it works try the following:

echo "abc -1.2 def 2 3 hij" | awk -f column.awk

The output is:

abc       |      -1.2|def       |         2|         3|hij

There are 2 tunable parameters inside the .awk script:

width: the default field with (used for alignment)
separator: used to separate output columns

Related Solutions

Ubuntu – Piping the output of comand columns

Expanding on @dessert's answer, you need a bit more work to make your colored ls version behave just like the real ls in (hopefully?) all cases. The problem is that ls is not meant to be parsed but intended for human eyes only. For that purpose, it strongly adapts how it works depending on the environment, e.g. whether it is connected to a terminal or outputting to a pipe.

First, you don't need a separate /bin/lsslss executable to avoid recursion. Use the shell built-in command to call an executable from the disk, ignoring any shell functions or aliases of the same name.

Second, $* gives you all function arguments as a single string, which is then subject to word-splitting because it is unquoted. This can give surprisingly wrong results if you have arguments with spaces. Always use "$@", which exactly preserves all arguments as they were originally given, with no concatenation or further splitting.

And third, depending on where you put the definition, the syntax ls () { ... ;} to define a function might not work if ls is already an alias, because alias expansion happens first, causing a syntax error. Use the explicit syntax by writing function before it.

Then, we can use ls' -C flag to manually enable column output:

function ls() { command ls -C "$@" | lolcat ;}

However, if we just do that and pipe the output through lolcat (or anything else), you will notice that it doesn't use the full width of your terminal any more, but only 80 columns at most. This is because it can not detect the terminal width if its standard out is no longer directly connected to it. Your shell still knows the terminal though, and it populates the COLUMNS variable with the width it detected. But, as this variable is not exported by default, ls does not see this value. We can manually pass it on just for this command like:

function ls() { COLUMNS="$COLUMNS" command ls -C "$@" | lolcat ;}

Now we should always get the correct width, but what happens if we really want to pipe ls through something else? Normally you shouldn't do that, because as I said in the beginning, ls should never be parsed. Sometimes it might still be useful though (and some scripts might sadly rely on it), so let's try to at least preserve the original behaviour then. Right now, we would always get the columns as output for e.g. ls | cat. (It's not colored any more there because lolcat also checks if it outputs to a terminal or pipe and switches colors off in the latter case)

Let's add a check to our function that uses the plain real ls if it is piped and our fancy rainbow column version only for terminal view. Whether standard out (file descriptor 1) is a terminal/TTY can simply be checked with [[ -t 1 ]]:

function ls() { 
    if [[ -t 1 ]] ; then COLUMNS="$COLUMNS" command ls -C "$@" | lolcat ; else command ls "$@" ; fi
}

I think that should suffice to catch all cases where special/different behaviour from ls is expected, so that your function only adds color when viewed directly in a terminal and otherwise does not alter anything.

Best Answer

Related Solutions

Ubuntu – Piping the output of comand columns

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