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# **head**
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```markdown
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用法：head [选项]... [文件]...
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Print the first 10 lines of each FILE to standard output.
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With more than one FILE, precede each with a header giving the file name.
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With no FILE, or when FILE is -, read standard input.
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Mandatory arguments to long options are mandatory for short options too.
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-c, --bytes=[-]K print the first K bytes of each file;
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with the leading '-', print all but the last
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K bytes of each file
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-n, --lines=[-]K print the first K lines instead of the first 10;
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with the leading '-', print all but the last
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K lines of each file
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-q, --quiet, --silent 不显示包含给定文件名的文件头
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-v, --verbose 总是显示包含给定文件名的文件头
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K 后面可以跟乘号:
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b 512, kB 1000, K 1024, MB 1000*1000, M 1024*1024,
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GB 1000*1000*1000, G 1024*1024*1024, 对于T, P, E, Z, Y 同样适用
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```
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## 实例
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```bash
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head -1 file # 显示file文件第一行
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head -n1 /etc/issue # 查看操作系统版本,不一定每个系统都能看到
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```
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