Linux fold命令

mytomorrow

, w9 O  D( G7 N- q4 mLinux fold命令用于限制文件列宽。
; }" Y- O# ]: ]  l9 V/ n6 b9 B% H
fold指令会从指定的文件里读取内容，将超过限定列宽的列加入增列字符后，输出到标准输出设备。若不指定任何文件名称，或是所给予的文件名为"-"，则fold指令会从标准输入设备读取数据。
4 y, G3 U; p( t# f" M1 {1 \

; |: h  V% \4 ^/ m) b5 K; K语法
7 S) L0 x$ `4 ~; Z5 _# Y" c4 _
fold [-bs][-w<每列行数>][--help][--version][文件...]



' W' A% f) Q- g9 J参数：

-b或--bytes 以Byte为单位计算列宽，而非采用行数编号为单位。
& l. s( T! r" c, P0 V2 x7 X-s或--spaces 以空格字符作为换列点。
-w<每列行数>或--width<每列行数> 设置每列的最大行数。
5 _& |1 T* f! ~# y9 C1 m8 H9 e--help 在线帮助。
--version 显示版本信息。
3 _7 h% ^, D, f4 ^

4 s, F! d7 l8 S5 e
实例
, `2 [% `9 _: {7 y
将一个名为testfile 的文件的行折叠成宽度为30，可使用如下命令：
; S2 Z# {! Z* `' G
' G4 i' o5 b, Lfold -w 30 testfile

% q2 J+ E  N7 ]/ U: F/ j  Z
% }- i) ~# Y2 i7 N为了对比，先将testfile文件输出如下：

7 i9 f9 t  g7 j$ cat testfile #查看testfile 中的内容  
1 M6 a4 C$ A; S* j- L4 xLinux networks are becoming more and more common, but
0 o  Y0 v, ?' qsecurity is often an overlooked  
issue. Unfortunately, in today’s environment all networks
are potential hacker targets,  
from top-secret military research networks to small home LANs.  
Linux Network Security focuses on securing Linux in a
: P; }$ ?1 b' ]+ C9 V1 l3 X3 o/ \networked environment, where the  
security of the entire network needs to be considered
rather than just isolated machines.  
It uses a mix of theory and practical techniques to
. l8 t2 s8 I1 N* V! xteach administrators how to install and  
use security applications, as well as how the
4 @  W& m  D* H4 Vapplications work and why they are necessary.
2 a) {9 Z) v% b& C, o: h0 E# z9 ]

然后使用fold命令折叠显示：

$ fold -w 30 testfile #行折叠成宽度为30，显示testfile 文件  
Linux networks are becoming mo  
, `4 Q5 G1 y: k' ~: s7 U1 G& hre and more common, but securi  
' c$ Q# U0 i6 Aty is often an overlooked issu  
e. Unfortunately, in today’s  
environment all networks are  
potential hacker targets, from  
" l! k) _1 I& i' U: d4 M- m$ Mtop-secret military research  
networks to small home LANs.  
8 M9 t& }% a- }! C1 bLinux Network Security focuses  
. b' ^( p6 E+ A0 w- x/ u$ Ton securing Linux in a networ  
* M7 ^5 |' x7 M4 d, aked environment, where the sec  
urity of the entire network ne  
eds to be considered rather th  
. e- r! p# u  Y4 g. g/ uan just isolated machines. It  
0 ~& W- r; G* h1 k- Z2 kuses a mix of theory and pract  
ical techniques to teach admin  
istrators how to install and u  
2 M# a- u1 H0 U7 nse security applications, as w  
1 N5 q' N, o+ O% a# Z; f, @: |( nell as how the applications wo  
rk and why they are necessary
& R+ u1 T! |) {; k

AustCor1

Linux fold命令

yin123

Linux fold命令用于限制文件列宽

regngfpcb

fold指令会从指定的文件里读取内容，将超过限定列宽的列加入增列字符后，输出到标准输出设备