越界最不惊讶：
bash-5.0$ (for i in {1..1000010}; do echo $i; done) | nl | tail -24
999987 999987
999988 999988
999989 999989
999990 999990
999991 999991
999992 999992
999993 999993
999994 999994
999995 999995
999996 999996
999997 999997
999998 999998
999999 999999
000000 1000000
000001 1000001
000002 1000002
000003 1000003
000004 1000004
000005 1000005
000006 1000006
000007 1000007
000008 1000008
000009 1000009
000010 1000010
bash-5.0$ uname -a
Darwin llc.local 19.4.0 Darwin Kernel Version 19.4.0: Wed Mar 4 22:28:40 PST 20
20; root:xnu-6153.101.6~15/RELEASE_X86_64 x86_64
bash-5.0$ sw_vers
ProductName: Mac OS X
ProductVersion: 10.15.4
[...]
bash-5.0$ _
与预期比较：
admin@ip-w-x-y-z:~$ (for i in {1..1000010}; do echo $i; done) | nl | tail -24
999987 999987
999988 999988
999989 999989
999990 999990
999991 999991
999992 999992
999993 999993
999994 999994
999995 999995
999996 999996
999997 999997
999998 999998
999999 999999
1000000 1000000
1000001 1000001
1000002 1000002
1000003 1000003
1000004 1000004
1000005 1000005
1000006 1000006
1000007 1000007
1000008 1000008
1000009 1000009
1000010 1000010
admin@ip-w-x-y-z:~$ uname -a
Linux ip-w-x-y-z 4.9.0-9-amd64 #1 SMP Debian 4.9.168-1+deb9u4 (2019-07-19)
x86_64 GNU/Linux
admin@ip-w-x-y-z:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description: Debian GNU/Linux 9.9 (stretch)
Release: 9.9
Codename: stretch
admin@ip-w-x-y-z:~$ _
我很好奇你对此有何想法以及如何克服。谢谢。
答案1
默认宽度添加的数字nl是 6。这在nl手册中以及由 POSIX 标准指定。
nl如果数字长于宽度，macOS会截断数字（并且手册记录了这一点），而 GNUnl则不会（但没有记录这一点）。标准文本似乎不允许这两种行为。
要对需要超过 6 位数字的行进行编号，请使用以下-w选项指定更大的宽度nl：
$ (for i in {1..1000010}; do echo $i; done) | nl -w 7 | tail -24
999987 999987
999988 999988
999989 999989
999990 999990
999991 999991
999992 999992
999993 999993
999994 999994
999995 999995
999996 999996
999997 999997
999998 999998
999999 999999
1000000 1000000
1000001 1000001
1000002 1000002
1000003 1000003
1000004 1000004
1000005 1000005
1000006 1000006
1000007 1000007
1000008 1000008
1000009 1000009
1000010 1000010