Linux fold命令

Linux 命令大全 Linux 命令大全

Linux fold命令用於限制檔列寬。

fold指令會從指定的檔裏讀取內容，將超過限定列寬的列加入增列字元後，輸出到標準輸出設備。若不指定任何檔案名稱，或是所給予的檔案名為"-"，則fold指令會從標準輸入設備讀取數據。

語法

fold [-bs][-w<每列行數>][--help][--version][檔...]

參數：

  • -b或--bytes 以Byte為單位計算列寬，而非採用行數編號為單位。
  • -s或--spaces 以空格字元作為換列點。
  • -w<每列行數>或--width<每列行數> 設置每列的最大行數。
  • --help 線上幫助。
  • --version 顯示版本資訊。

實例

將一個名為testfile 的檔的行折疊成寬度為30，可使用如下命令： 

fold -w 30 testfile

為了對比，先將testfile檔輸出如下：

$ cat testfile #查看testfile 中的內容
Linux networks are becoming more and more common, but
security 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
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
teach administrators how to install and
use security applications, as well as how the
applications work and why they are necessary.

然後使用fold命令折疊顯示：

$ fold -w 30 testfile #行折疊成寬度為30，顯示testfile 檔

Linux networks are becoming mo
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.
Linux Network Security focuses
on securing Linux in a networ
ked environment, where the sec
urity of the entire network ne
eds to be considered rather th
an just isolated machines. It
uses a mix of theory and pract
ical techniques to teach admin
istrators how to install and u
se security applications, as w
ell as how the applications wo
rk and why they are necessary

Linux 命令大全 Linux 命令大全