creating a sequence of numbers, one per line in a file

Question

Is there a way to create out of thin air, a file that is a sequence of numbers, starting at a given number, one per line?

something like

magic_command start 100 lines 5 > b.txt

and then, b.txt would be

100
101
102
103
104

Answer 1

There is already a command for this:

seq 100 104

will print these numbers on separate lines: 100 101 102 103 104

So just direct this output into a file:

seq 100 104 > my_file.txt

and seq 100 2 104 will print in increments of two, namely: 100, 102, 104

Answer 2

Linux ships with the seq command which does exactly that. If you don't have the seq command, it's an easy one-liner:

i=100; while [ $i -le 104 ]; do echo $i; i=$((i+1)); done >b.txt

or in ksh/bash/zsh

for ((i=100; i<=104; i++)); do echo $i; done >b.txt

or in zsh

print -l {100..104} >b.txt

Answer 3

perl:

perl -le 'print for 100..104'

bc:

echo 'for (i = 100 ; i <= 104 ; ++i) i' | bc

dc:

echo '100 104 sb [p 1 + d lb !<m] sm lm x' | dc

Answer 4

If you don't mind a space in front of most of them:

echo -e {100..104}\\n >numbers-file.txt

Without the space but with an extra command:

echo {100..104} | sed 's/ /\n/g' >numbers-file.txt

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Edit for a bonus vim command (open vim):

i100[esc]qqyyp[ctrl-a]q2@q:w numbers-file.txt

For more numbers, increase 2 accordingly.