Re: [Help-bash] Ruler

[Greg Wooledge]

On Fri, Dec 18, 2015 at 01:03:07AM +0000, Val Krem wrote:
> I want write it in script and put in the bin so that I can call from anywhere 
> to use it.
> 
> >bash$ ruler   filename
> 
> can you please help me how to do that.

To refresh everyone's memory (I am bringing this BACK to the mailing
list where it belongs), here's the function I wrote:


ruler() {
    local cols=${COLUMNS:-$(tput cols)}
    local i n tmp
    if (( ${#_ruler_line1} < cols )); then
        n=$(( ${#_ruler_line1} / 10 ))
        for ((i=n+1; i*10 <= cols; i++)); do
            printf -v tmp %10d "$i"
            _ruler_line1+=$tmp
        done
    fi
    while (( ${#_ruler_line2} < cols )); do
        _ruler_line2+=1234567890
    done
    echo "${_ruler_line1:0:cols}"
    echo "${_ruler_line2:0:cols}"
    cat "$@"
}


If you simply paste that into your ~/.bashrc file and then open a new
terminal (or run "exec bash" in an existing terminal) you can use it
as a command.

If you really want to convert it into a script, then open a new file
(call it "ruler", with no extension) and put this in it:


#!/usr/bin/env bash
cols=${COLUMNS:-$(tput cols)}
unset _ruler_line1 _ruler_line2
if (( ${#_ruler_line1} < cols )); then
    n=$(( ${#_ruler_line1} / 10 ))
    for ((i=n+1; i*10 <= cols; i++)); do
        printf -v tmp %10d "$i"
        _ruler_line1+=$tmp
    done
fi
while (( ${#_ruler_line2} < cols )); do
    _ruler_line2+=1234567890
done
echo "${_ruler_line1:0:cols}"
echo "${_ruler_line2:0:cols}"
cat "$@"


Then move or copy the file to any directory that is in your PATH variable.
Personally I would suggest that you create the directory ~/bin/ and put
the script in there.  Then add :~/bin to the end of your PATH variable,
which you would do in one of your dot files.  If you don't like this
approach, you can become super-user and put the script in /usr/local/bin.

In any case, wherever you end up putting the script, you need to make
it executable.  So, in addition to moving/copying it, you also need to
run:

   chmod +x ruler

Doing it as a function is simpler, and more efficient.  Doing it as a
script in a global location like /usr/local/bin makes it available to
other users on your system, and allows it to be invoked from other
commands like find.

See also:

http://mywiki.wooledge.org/BashGuide
http://mywiki.wooledge.org/DotFiles