Linux fold command
Linux fold command is used to limit the file column width.
fold instruction reads the content from the specified file will be more than the width of the column after column added additional characters to the standard output device. If not specify any file name or file name given by "-", then fold instruction reads data from the standard input device.
grammar
fold [-bs][-w<每列行数>][--help][--version][文件...]
Parameters:
- -b or --bytes in Byte column width for the unit, rather than the use of the line number of units.
- -s or a space character as --spaces Breaks points.
- -w <number of lines per column> or --width <number of lines per column> Sets the maximum number of lines per column.
- --help online help.
- --version display version information.
Examples
The row named testfile file folded into a width of 30, use the following command:
fold -w 30 testfile
For comparison, the first testfile file output is as follows:
$ cat testfile #查看testfile 中的内容 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.
Then use the fold folding display command:
$ fold -w 30 testfile #行折叠成宽度为30，显示testfile 文件 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