Indenting Multi-Line Output in a Shell Script

Indenting multi-line output in a shell script

Pipe it to sed to insert 2 spaces at the beginning of each line.

git status | sed 's/^/  /'

Indent long line stdout

I'd use awk for this.

awk -v width="$COLUMNS" -v spaces=4 '
BEGIN {
  pad = sprintf("%*s", spaces, "") # generate `spaces` spaces
}
NF {                               # if current line is not empty
  while (length > width) {         # while length of current line is greater than `width`
    print substr($0, 1, width)     # print `width` chars from the beginning of it
    $0 = pad substr($0, width + 1) # and leave `pad` + remaining chars
  }
  if ($0 != "")                    # if there are remaining chars
    print                          # print them too 
  next
} 1' file

In one line:

awk -v w="$COLUMNS" -v s=4 'BEGIN{p=sprintf("%*s",s,"")} NF{while(length>w){print substr($0,1,w);$0=p substr($0,w+1)} if($0!="") print;next} 1'

As @Mark suggested in comments, you can put this in a function and add it to .bashrc for ease of use.

function wrap() {
  awk -v w="$COLUMNS" -v s=4 'BEGIN{p=sprintf("%*s",s,"")} NF{while(length>w){print substr($0,1,w);$0=p substr($0,w+1)} if($0!="") print;next} 1'
}

Usage:

ls -l | wrap

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Edit by Ed Morton per request:

Very similar to oguzismails script above but should work with Busybox or any other awk:

$ cat tst.awk
BEGIN { pad = sprintf("%" spaces "s","") }
{
    while ( length($0) > width ) {
        printf "%s", substr($0,1,width)
        $0 = substr($0,width+1)
        if ( $0 != "" ) {
            print ""
            $0 = pad $0
        }
    }
    print
}
$
$ echo '123456789012345678901234567890' | awk -v spaces=3 -v width=30 -f tst.awk
123456789012345678901234567890
$ echo '123456789012345678901234567890' | awk -v spaces=3 -v width=15 -f tst.awk
123456789012345
   678901234567
   890
$ echo '' | awk -v spaces=3 -v width=15 -f tst.awk

$

That first test case is to show that you don't get a blank line printed after a full-width input line and the third is to show that it doesn't delete blank rows. Normally I'd have used sprintf("%*s",spaces,"") to create the pad string but I see in a comment that that doesn't work in the apparently non-POSIX awk you're using.

How to output a multiline string in Bash?

Here documents are often used for this purpose.

cat << EOF
usage: up [--level <n>| -n <levels>][--help][--version]

Report bugs to: 
up home page:
EOF

They are supported in all Bourne-derived shells including all versions of Bash.

Multi-line string with extra space (preserved indentation)

Heredoc sounds more convenient for this purpose. It is used to send multiple commands to a command interpreter program like ex or cat

cat << EndOfMessage
This is line 1.
This is line 2.
Line 3.
EndOfMessage

The string after << indicates where to stop.

To send these lines to a file, use:

cat > $FILE <<- EOM
Line 1.
Line 2.
EOM

You could also store these lines to a variable:

read -r -d '' VAR << EOM
This is line 1.
This is line 2.
Line 3.
EOM

This stores the lines to the variable named VAR.

When printing, remember the quotes around the variable otherwise you won't see the newline characters.

echo "$VAR"

Even better, you can use indentation to make it stand out more in your code. This time just add a - after << to stop the tabs from appearing.

read -r -d '' VAR <<- EOM
    This is line 1.
    This is line 2.
    Line 3.
EOM

But then you must use tabs, not spaces, for indentation in your code.

Indenting read input when it contains multiple lines

It sounds like the issue is with the way read works. Read echos back keystrokes and I think perhaps because of stdout buffer it is writtern before the echo statements are flushed.

Using a combo of echo command and the -e argument to read (interactive) fixes this in my testing.

#!/bin/bash
echo "Provide inputs:"
until [[ "$message" = "three" ]]; do
    echo -ne "> "
    read -e message
    myArray+=($message) #Input added to array for later processing
done

Bash multi-line command with input | output

The reason for this happening to me was a unique issue I was having with my IDE .. It was inserting an actual character for a line break rather than just a physical line-break itself. The problem wasn't the syntax I was attempting, rather the inserted characters on save. Thanks to all who thoughtfully answered my question. My original un-escaped syntax was correct to begin with.

Capturing multiple line output into a Bash variable

Actually, RESULT contains what you want — to demonstrate:

echo "$RESULT"

What you show is what you get from:

echo $RESULT

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As noted in the comments, the difference is that (1) the double-quoted version of the variable (echo "$RESULT") preserves internal spacing of the value exactly as it is represented in the variable — newlines, tabs, multiple blanks and all — whereas (2) the unquoted version (echo $RESULT) replaces each sequence of one or more blanks, tabs and newlines with a single space. Thus (1) preserves the shape of the input variable, whereas (2) creates a potentially very long single line of output with 'words' separated by single spaces (where a 'word' is a sequence of non-whitespace characters; there needn't be any alphanumerics in any of the words).

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