Linux fold命令

mytomorrow

Linux fold命令用于限制文件列宽。

) U& i- c3 t0 l$ y3 J9 tfold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。


* n2 [9 I/ L5 r: p语法
! y3 P& q( w" p
fold [-bs][-w<每列行数>][--help][--version][文件...]
# b5 K! i( m! e/ j2 Y


5 q0 m9 J6 B& c  S. q8 q, e( K参数：

9 T: F. @7 r; G, ^) ?, L-b或--bytes 以Byte为单位计算列宽，而非采用行数编号为单位。
-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。
! H3 d! ]5 u; _% T5 S, y--help 在线帮助。
& f, H  B; H( C  F& U--version 显示版本信息。

7 H8 g0 j5 J5 m/ v" \+ J: Q! V
* x; A: Q; |2 u( `% {
) ^% T: R: O+ I! o实例
; Y: G/ @5 X- \) I/ f
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：

% Z+ v2 k2 O7 o0 K/ o0 Bfold -w 30 testfile

# O3 l, Y$ `. i
; H. l; ?9 P' N& T8 M7 E为了对比，先将testfile文件输出如下：

& \& P* d7 P6 q0 k5 f1 m+ q$ cat testfile #查看testfile 中的内容  
Linux networks are becoming more and more common, but
- O* C/ a# \% Ssecurity is often an overlooked  
3 I# _% d' I8 X; f  Gissue. Unfortunately, in today’s environment all networks
7 F5 Y* Q2 O0 T# E! ~are potential hacker targets,  
from top-secret military research networks to small home LANs.  
Linux Network Security focuses on securing Linux in a
networked environment, where the  
1 G( t% E, F& Y! Q3 o' ]8 @security of the entire network needs to be considered
rather than just isolated machines.  
  _& Z1 B- Z( J$ V/ FIt uses a mix of theory and practical techniques to
teach administrators how to install and  
use security applications, as well as how the
8 h' G6 ?. N: B; [applications work and why they are necessary.


1 ~' k3 y* s: L& V8 r6 U) _然后使用fold命令折叠显示：
2 Y8 Y9 Q( H! \  L
3 y* S2 `/ }9 o* \1 @! k$ fold -w 30 testfile #行折叠成宽度为30，显示testfile 文件  
% Z: P! A4 t0 K& N9 y7 L' a. h8 kLinux networks are becoming mo  
; q; q& v3 L: l. V3 w. t- e: x* N- e! _re and more common, but securi  
ty is often an overlooked issu  
e. Unfortunately, in today’s  
environment all networks are  
potential hacker targets, from  
top-secret military research  
networks to small home LANs.  
. P: a0 E2 `+ @7 F& I2 Y  k" C7 F& d2 {Linux Network Security focuses  
on securing Linux in a networ  
" S& f9 e0 t, A" @" z2 Sked environment, where the sec  
urity of the entire network ne  
: u" g! ^. ?. U! {. Beds to be considered rather th  
an just isolated machines. It  
0 T: u" w% f& n0 U! kuses a mix of theory and pract  
( C$ N' t! @. d4 l( ~ical techniques to teach admin  
istrators how to install and u  
- K+ I1 U3 t: n2 S& f# rse security applications, as w  
ell as how the applications wo  
rk and why they are necessary
: a. G" _2 u5 a0 X  N: b

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