less
less程序可以查看一个文本文件的内容：
$ less .bashrc
# ~/.bashrc: executed by bash(1) for non-login shells.
# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
# for examples
# If not running interactively, don't do anything
case $- in
*i*) ;;
*) return;;
esac
# 省略
上面的例子使用less程序查看了.bashrc文件的内容。
常用的操作如下：
| 操作 | 功能 |
|---|---|
| 空格键 | 向下翻页 |
| 按键 pagedown | 向下翻页 |
| 按键 pageup | 向上翻页 |
| /string | 向下搜索string |
| ?string | 向上搜索string |
| n | 搜索下一个 |
| N | 搜索上一个 |
| q | 离开less |
cat
cat命令也可以查看文本文件内容，它的功能很多，下面是一些常见的：
-
-A：显示特殊字符。 -
-n：显示行号。 -
-b：仅对非空白行显示行号。
下面使用cat查看文件.bashrc内容：
$ cat .bashrc
# ~/.bashrc: executed by bash(1) for non-login shells.
# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
# for examples
# 省略
使用-n选项查看行号：
$ cat -n .bashrc
1 # ~/.bashrc: executed by bash(1) for non-login shells.
2 # see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
3 # for examples
4
5 # If not running interactively, don't do anything
6 case $- in
7 *i*) ;;
8 *) return;;
9 esac
# 省略
使用-b仅对非空白行显示行号：
$ cat -b .bashrc
1 # ~/.bashrc: executed by bash(1) for non-login shells.
2 # see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
3 # for examples
4 # If not running interactively, don't do anything
5 case $- in
6 *i*) ;;
7 *) return;;
8 esac
# 省略
-A选项可以在文档中将Tab用^I显示，将断行符号用$显示：
$ cat -A .bashrc
# ~/.bashrc: executed by bash(1) for non-login shells.$
# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)$
# for examples$
$
# If not running interactively, don't do anything$
case $- in$
*i*) ;;$
*) return;;$
esac$
可以看到，每行的最后都有断行符号$。
head tail
head命令显示文档的“头”，tail命令显示文档的“尾”。
使用head显示文档的前5行：
$ head -n 5 .bashrc
# ~/.bashrc: executed by bash(1) for non-login shells.
# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
# for examples
# If not running interactively, don't do anything
$
使用tail显示文档的最后5行：
$ tail -n 5 .bashrc
. /usr/share/bash-completion/bash_completion
elif [ -f /etc/bash_completion ]; then
. /etc/bash_completion
fi
fi
$
