Format bash output

ceashton · 08-15-2007, 06:26 PM

Hi,

I'm writing a bash script for which there is a --longhelp option, which outputs several screen full of helpful information ;-). I am wandering how it is best to format these pages?

In the past I have just used:

Code:

echo "some text"
echo "some more text"
echo "yet more text"

or

Code:

echo -e "some text
some more text
yet more text"

Is there an easy way to specify a certain width to contain all the text - or indeed to fill the screen's width - instead of formatting the text as in my example?

Many thanks

Chris

makyo · 08-15-2007, 06:39 PM

Hi.

Here is one solution:

Code:

#!/bin/sh

# @(#) s1       Demonstrate fmt and here document.

set -o nounset
echo

echo "GNU bash $BASH_VERSION" >&2
fmt --version | head -1

echo

fmt <<'EOF'

        This is part
        of a paragraph that
        can be entered and fixed up
        in short pieces, and will
        be tidied up by fmt.

You can use indents or not as you please, and if your lines are too long, fmt will handle that as well.

See man fmt for details.

EOF

exit 0

Producing:

Code:

% ./s1

GNU bash 2.05b.0(1)-release
fmt (coreutils) 5.2.1


        This is part of a paragraph that can be entered and fixed up in
        short pieces, and will be tidied up by fmt.

You can use indents or not as you please, and if your lines are too long,
fmt will handle that as well.

See man fmt for details.

cheers, makyo

ceashton · 08-15-2007, 06:47 PM

Thanks for the quick reply, this is just what I was looking for. I knew there would be a command for it, just didn't know what to look up!

Thanks once again,

Chris

cfaj · 08-17-2007, 12:16 PM

Quote:

Originally Posted by ceashton

Hi,

I'm writing a bash script for which there is a --longhelp option, which outputs several screen full of helpful information ;-). I am wandering how it is best to format these pages?

In the past I have just used:

Code:

echo "some text"
echo "some more text"
echo "yet more text"

or

Code:

echo -e "some text
some more text
yet more text"

Is there an easy way to specify a certain width to contain all the text - or indeed to fill the screen's width - instead of formatting the text as in my example?

You can use fold (fmt is not standard), or, to speed things up if you will be calling it several times, this shell function:
Code:
wordwrap() {
   case $1 in
       --) shift ;;
       -[0-9]*) ww=${1#-}; shift ;;
       *) ww=$(( ${COLUMNS:-80} - 8 )) ;;
   esac
   str=
   sub=0
   len=0
   ww=$(( $ww - ${WW_INDENT:=0} ))
   for word
   do
     len=$(( ${#str} + ${#word} ))
     if [ $len -le $ww ]
     then
       str=${str:+$str }$word
     else
       printf "%${WW_INDENT:-0}s%s\n" "" "$str"
       len=${#str}
       str=$word
     fi
   done
   printf "%${WW_INDENT:-0}s%s\n" "" "$str"
}
The default width is 8 characters less than your terminal window (defaults to 72 if COLUMNS is not set). This can be changed by specifying a width, -NN, as the first parameter.

If the first word to be printed could be interpreted as a width setting, use -- as the first argument.

Text can be indented by setting WW_INDENT.