echo:显示文本
NAME
echo - display a line of text
SYNOPSIS
echo [SHORT-OPTION]... [STRING]...
echo LONG-OPTION
-n
[[email protected] doc]# echo -n
[[email protected] doc]# echo
[[email protected] doc]#
[[email protected] doc]# echo -n "this year is 2017,\n the day is Feb 11"
this year is 2017,\n the day is Feb 11[[email protected] doc]#
-e:文本开启转义符
[[email protected] doc]# echo "this year is 2017,\n the day is Feb 11"
this year is 2017,\n the day is Feb 11
[[email protected] doc]# echo -e "this year is 2017,\n the day is Feb 11"
this year is 2017,
the day is Feb 11
printf:格式化并显示文本
PRINTF(1) User Commands PRINTF(1)
NAME
printf - format and print data
SYNOPSIS
printf FORMAT [ARGUMENT]...
printf OPTION
[[email protected] doc]# printf "this year is 2017,the day is Feb 11"
this year is 2017,the day is Feb 11[[email protected] doc]#
file 判断文件类型
该命令用来识别文件类型,也可用来辨别一些文件的编码格式。它是通过查看文件的头部信息来获取文件类型,而不是像Windows通过扩展名来确定文件类型的。
NAME
file - determine file type
SYNOPSIS
file [-bchikLNnprsvz0] [--apple] [--mime-encoding] [--mime-type] [-e testname] [-F separator]
[-f namefile] [-m magicfiles] file ...
file -C [-m magicfiles]
file [--help]
ELF:可执行链接文件
[[email protected] ~]$ file /bin/ls
/bin/ls: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.18, stripped