How to avoid printing a newline when seq completes

.seqgnu

To create a column header, looking like:

1234567890123456789

I (am trying to) use seq and echo:

seq -s '' 1 9 ; echo -n 0; seq -s '' 1 9

However, seq outputs a newline after each run. How can I avoid that?

Best Answer

Assuming you just want to print 1234567890123456789, you can do it with:

$ printf "%s" $(seq 1 9) $(seq 0 9)
1234567890123456789$

That won't have a trailing newline at all though, so maybe you prefer:

$ printf "%s" $(seq 1 9) $(seq 0 9) $'\n'
1234567890123456789
$

A few simpler choices if you don't need to use seq:

$ perl -le 'print 1..9,0,1..9'
1234567890123456789
$ printf "%s" {1..9} {0..9} $'\n'
1234567890123456789

Since you mentioned portability, I recommend you use the perl approach, or if you are likely to encounter systems without perl, and yet need the same command to run in shells including bash, sh, dash, tcsh etc, try Kamil's approach.

Related Solutions

Sed – Achieving Portability with sed -i (In-Place Editing)

GNU sed accepts an optional extension after -i. The extension must be in the same argument with no intervening space. This syntax also works on BSD sed.

sed -i.bak -e '…' SOMEFILE

Note that on BSD, -i also changes the behavior when there are multiple input files: they are processed independently (so e.g. $ matches the last line of each file). Also this won't work on BusyBox.

If you don't want to use backup files, you could check which version of sed is available.

case $(sed --help 2>&1) in
  *GNU*) set sed -i;;
  *) set sed -i '';;
esac
"$@" -e '…' "$file"

Or alternatively, to avoid clobbering the positional parameters, define a function.

case $(sed --help 2>&1) in
  *GNU*) sed_i () { sed -i "$@"; };;
  *) sed_i () { sed -i '' "$@"; };;
esac
sed_i -e '…' "$file"

If you don't want to bother, use Perl.

perl -i -pe '…' "$file"

If you want to write a portable script, don't use -i — it isn't in POSIX. Do manually what sed does under the hood — it's only one more line of code.

sed -e '…' "$file" >"$file.new"
mv -- "$file.new" "$file"

Command Line – How to Randomize the Output from seq

You can just pipe the output to shuf.

$ seq 100 | shuf

Example

$ seq 10 | shuf
2
6
4
8
1
3
10
7
9
5

If you want the output to be horizontal then pipe it to paste.

$ seq 10 | shuf | paste - -s -d ' '
1 6 9 3 8 4 10 7 2 5 

$ seq 10 | shuf | paste - -s -d ' '
7 4 6 1 8 3 10 5 9 2 

$ seq 10 | shuf | paste - -s -d ' '
9 8 3 6 1 2 10 4 7 5

Want it with commas in between? Change the delimiter to paste:

$ seq 10 | shuf | paste - -s -d ','
2,4,9,1,8,7,3,5,10,6

Best Answer

Related Solutions

Sed – Achieving Portability with sed -i (In-Place Editing)

Command Line – How to Randomize the Output from seq

Example

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