文件内容查看

概述

• cat 从开头开始显示文件内容
• tac 从最后一行开始显示，可以看成cat倒着写
• nl 显示行数
• more 可以翻页查看，但不能向上翻页，enter为一行一行翻页，空格直接翻页
• less 可以上下翻页，上下键翻页，n向上翻页，N向下翻页， /（字符）向下查询字符， ?（字符）向上查询字符，q离开less
• head 只看头几行
• tail 只看尾部几行

cat 从开头开始显示文件内容

• 参数
• -n 列出行数 (空白行也会标记行数，与-b相反)

[root@LuoKing etc]# cat -n csh.login 
     1	# /etc/csh.login
     2	
     3	# System wide environment and startup programs, for login setup
     4	
     5	if ( ! ${?PATH} ) then
     6	        if ( $uid == 0 ) then
     7			setenv PATH "/usr/local/sbin:/usr/sbin:/usr/local/bin:/usr/bin"
     8	        else
     9			setenv PATH "/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin"
    10	        endif
    11	else
    12		#add sbin directories to the path
    13		foreach p ( /usr/local/sbin /usr/sbin )
    14			switch (":${PATH}:")
    15			case "*:${p}:*":
    16				breaksw
    17			default:
    18				if ( $uid == 0 ) then
    19	                        	set path = ( ${p} ${path:q} )
    20				else
    21	                        	set path = ( ${path:q} ${p} )
    22				endif
    23				breaksw
    24			endsw
    25		end
    26	endif
    27	
    28	setenv HOSTNAME `/usr/bin/hostname`
    29	set history=1000
    30	
    31	if ( -d /etc/profile.d ) then
    32	        set nonomatch
    33	        foreach i ( /etc/profile.d/*.csh /etc/profile.d/csh.local )
    34	                if ( -r "$i" ) then
    35		                        if ($?prompt) then
    36		                              source "$i"
    37		                        else
    38		                              source "$i" >& /dev/null
    39		                        endif
    40	                endif
    41	        end
    42	        unset i nonomatch
    43	endif

• -b(标记行数，不会标记空白行)

[root@LuoKing etc]# cat -b csh.login 
     1	# /etc/csh.login

     2	# System wide environment and startup programs, for login setup

     3	if ( ! ${?PATH} ) then
     4	        if ( $uid == 0 ) then
     5			setenv PATH "/usr/local/sbin:/usr/sbin:/usr/local/bin:/usr/bin"
     6	        else
     7			setenv PATH "/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin"
     8	        endif
     9	else
    10		#add sbin directories to the path
    11		foreach p ( /usr/local/sbin /usr/sbin )
    12			switch (":${PATH}:")
    13			case "*:${p}:*":
    14				breaksw
    15			default:
    16				if ( $uid == 0 ) then
    17	                        	set path = ( ${p} ${path:q} )
    18				else
    19	                        	set path = ( ${path:q} ${p} )
    20				endif
    21				breaksw
    22			endsw
    23		end
    24	endif

    25	setenv HOSTNAME `/usr/bin/hostname`
    26	set history=1000

    27	if ( -d /etc/profile.d ) then
    28	        set nonomatch
    29	        foreach i ( /etc/profile.d/*.csh /etc/profile.d/csh.local )
    30	                if ( -r "$i" ) then
    31		                        if ($?prompt) then
    32		                              source "$i"
    33		                        else
    34		                              source "$i" >& /dev/null
    35		                        endif
    36	                endif
    37	        end
    38	        unset i nonomatch
    39	endif

tac 文件内容从最后一行开始显示

[root@LuoKing etc]# tac csh.login 
endif
        unset i nonomatch
        end
                endif
	                        endif
	                              source "$i" >& /dev/null
	                        else
	                              source "$i"
	                        if ($?prompt) then
                if ( -r "$i" ) then
        foreach i ( /etc/profile.d/*.csh /etc/profile.d/csh.local )
        set nonomatch
if ( -d /etc/profile.d ) then

set history=1000
setenv HOSTNAME `/usr/bin/hostname`

endif
	end
		endsw
			breaksw
			endif
                        	set path = ( ${path:q} ${p} )
			else
                        	set path = ( ${p} ${path:q} )
			if ( $uid == 0 ) then
		default:
			breaksw
		case "*:${p}:*":
		switch (":${PATH}:")
	foreach p ( /usr/local/sbin /usr/sbin )
	#add sbin directories to the path
else
        endif
		setenv PATH "/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin"
        else
		setenv PATH "/usr/local/sbin:/usr/sbin:/usr/local/bin:/usr/bin"
        if ( $uid == 0 ) then
if ( ! ${?PATH} ) then

# System wide environment and startup programs, for login setup

# /etc/csh.login

nl 显示行数

选项与参数：

• -b ：指定行号指定的方式，主要有两种：-b a ：表示不论是否为空行，也同样列出行号(类似 cat -n)；-b t ：如果有空行，空的那一行不要列出行号(默认值)；

• -n ：列出行号表示的方法，主要有三种：-n ln ：行号在荧幕的最左方显示；-n rn ：行号在自己栏位的最右方显示，且不加 0 ；-n rz ：行号在自己栏位的最右方显示，且加 0 ；

• -w ：行号栏位的占用的位数。

[root@LuoKing etc]# nl csh.login  #默认空白行不显示行数
     1	# /etc/csh.login
       
     2	# System wide environment and startup programs, for login setup
       
     3	if ( ! ${?PATH} ) then
     4	        if ( $uid == 0 ) then
     5			setenv PATH "/usr/local/sbin:/usr/sbin:/usr/local/bin:/usr/bin"
     6	        else
     7			setenv PATH "/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin"
     8	        endif
     9	else
    10		#add sbin directories to the path
    11		foreach p ( /usr/local/sbin /usr/sbin )
    12			switch (":${PATH}:")
    13			case "*:${p}:*":
    14				breaksw
    15			default:
    16				if ( $uid == 0 ) then
    17	                        	set path = ( ${p} ${path:q} )
    18				else
    19	                        	set path = ( ${path:q} ${p} )
    20				endif
    21				breaksw
    22			endsw
    23		end
    24	endif
       
    25	setenv HOSTNAME `/usr/bin/hostname`
    26	set history=1000
       
    27	if ( -d /etc/profile.d ) then
    28	        set nonomatch
    29	        foreach i ( /etc/profile.d/*.csh /etc/profile.d/csh.local )
    30	                if ( -r "$i" ) then
    31		                        if ($?prompt) then
    32		                              source "$i"
    33		                        else
    34		                              source "$i" >& /dev/null
    35		                        endif
    36	                endif
    37	        end
    38	        unset i nonomatch
    39	endif

[root@LuoKing etc]# nl -b a csh.login # 空白行显示行数(all全部)
     1	# /etc/csh.login
     2	
     3	# System wide environment and startup programs, for login setup
     4	
     5	if ( ! ${?PATH} ) then
     6	        if ( $uid == 0 ) then
     7			setenv PATH "/usr/local/sbin:/usr/sbin:/usr/local/bin:/usr/bin"
     8	        else
     9			setenv PATH "/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin"
    10	        endif
    11	else
    12		#add sbin directories to the path
    13		foreach p ( /usr/local/sbin /usr/sbin )
    14			switch (":${PATH}:")
    15			case "*:${p}:*":
    16				breaksw
    17			default:
    18				if ( $uid == 0 ) then
    19	                        	set path = ( ${p} ${path:q} )
    20				else
    21	                        	set path = ( ${path:q} ${p} )
    22				endif
    23				breaksw
    24			endsw
    25		end
    26	endif
    27	
    28	setenv HOSTNAME `/usr/bin/hostname`
    29	set history=1000
    30	
    31	if ( -d /etc/profile.d ) then
    32	        set nonomatch
    33	        foreach i ( /etc/profile.d/*.csh /etc/profile.d/csh.local )
    34	                if ( -r "$i" ) then
    35		                        if ($?prompt) then
    36		                              source "$i"
    37		                        else
    38		                              source "$i" >& /dev/null
    39		                        endif
    40	                endif
    41	        end
    42	        unset i nonomatch
    43	endif

[root@LuoKing etc]# nl -b t csh.login  # 空白行不显示行数
     1	# /etc/csh.login
       
     2	# System wide environment and startup programs, for login setup
       
     3	if ( ! ${?PATH} ) then
     4	        if ( $uid == 0 ) then
     5			setenv PATH "/usr/local/sbin:/usr/sbin:/usr/local/bin:/usr/bin"
     6	        else
     7			setenv PATH "/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin"
     8	        endif
     9	else
    10		#add sbin directories to the path
    11		foreach p ( /usr/local/sbin /usr/sbin )
    12			switch (":${PATH}:")
    13			case "*:${p}:*":
    14				breaksw
    15			default:
    16				if ( $uid == 0 ) then
    17	                        	set path = ( ${p} ${path:q} )
    18				else
    19	                        	set path = ( ${path:q} ${p} )
    20				endif
    21				breaksw
    22			endsw
    23		end
    24	endif
       
    25	setenv HOSTNAME `/usr/bin/hostname`
    26	set history=1000
       
    27	if ( -d /etc/profile.d ) then
    28	        set nonomatch
    29	        foreach i ( /etc/profile.d/*.csh /etc/profile.d/csh.local )
    30	                if ( -r "$i" ) then
    31		                        if ($?prompt) then
    32		                              source "$i"
    33		                        else
    34		                              source "$i" >& /dev/null
    35		                        endif
    36	                endif
    37	        end
    38	        unset i nonomatch
    39	endif

more 一页一页翻动页面

在 more 这个程序的运行过程中，你有几个按键可以按的：

• 空白键 (space)：代表向下翻一页；

• Enter ：代表向下翻『一行』；

• /字串 ：代表在这个显示的内容当中，向下搜寻『字串』这个关键字；

• :f ：立刻显示出档名以及目前显示的行数；

• q ：代表立刻离开 more ，不再显示该文件内容。

• b 或 [ctrl]-b ：代表往回翻页，不过这动作只对文件有用，对管线无用。

[root@LuoKing etc]# more csh.login 
# /etc/csh.login

# System wide environment and startup programs, for login setup

if ( ! ${?PATH} ) then
        if ( $uid == 0 ) then
		setenv PATH "/usr/local/sbin:/usr/sbin:/usr/local/bin:/usr/bin"
        else
		setenv PATH "/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin"
        endif
else
	#add sbin directories to the path
	foreach p ( /usr/local/sbin /usr/sbin )
		switch (":${PATH}:")
		case "*:${p}:*":
			breaksw
--More--(38%) # 光标在这等待命令

less 支持往回翻

less运行时可以输入的命令有：

• 空白键 ：向下翻动一页；

• [pagedown]：向下翻动一页；

• [pageup] ：向上翻动一页；

• /字串 ：向下搜寻『字串』的功能；

• ?字串 ：向上搜寻『字串』的功能；

• n ：重复前一个搜寻 (与 / 或 ? 有关！)

• N ：反向的重复前一个搜寻 (与 / 或 ? 有关！)

• q ：离开 less 这个程序；

[root@LuoKing etc]# less csh.login 




# /etc/csh.login

# System wide environment and startup programs, for login setup

if ( ! ${?PATH} ) then
        if ( $uid == 0 ) then
                setenv PATH "/usr/local/sbin:/usr/sbin:/usr/local/bin:/usr/bin"
        else
                setenv PATH "/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin"
        endif
else
        #add sbin directories to the path
        foreach p ( /usr/local/sbin /usr/sbin )
                switch (":${PATH}:")
                case "*:${p}:*":
                        breaksw
                default:
: # 光标在此等待命令

head 显示开头几行

选项与参数：

-n 后面接数字，代表显示几行的意思！(包括空行)

[root@LuoKing etc]# head -n 20 csh.login 
# /etc/csh.login

# System wide environment and startup programs, for login setup

if ( ! ${?PATH} ) then
        if ( $uid == 0 ) then
		setenv PATH "/usr/local/sbin:/usr/sbin:/usr/local/bin:/usr/bin"
        else
		setenv PATH "/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin"
        endif
else
	#add sbin directories to the path
	foreach p ( /usr/local/sbin /usr/sbin )
		switch (":${PATH}:")
		case "*:${p}:*":
			breaksw
		default:
			if ( $uid == 0 ) then
                        	set path = ( ${p} ${path:q} )
			else

tail得到文件后几行

选项与参数：

-n 后面接数字，代表显示几行的意思！(包括空行)

[root@LuoKing etc]# head -n 20 csh.login 
# /etc/csh.login

# System wide environment and startup programs, for login setup

if ( ! ${?PATH} ) then
        if ( $uid == 0 ) then
		setenv PATH "/usr/local/sbin:/usr/sbin:/usr/local/bin:/usr/bin"
        else
		setenv PATH "/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin"
        endif
else
	#add sbin directories to the path
	foreach p ( /usr/local/sbin /usr/sbin )
		switch (":${PATH}:")
		case "*:${p}:*":
			breaksw
		default:
			if ( $uid == 0 ) then
                        	set path = ( ${p} ${path:q} )
			else
[root@LuoKing etc]# tail -n 20 csh.login 
		endsw
	end
endif

setenv HOSTNAME `/usr/bin/hostname`
set history=1000

if ( -d /etc/profile.d ) then
        set nonomatch
        foreach i ( /etc/profile.d/*.csh /etc/profile.d/csh.local )
                if ( -r "$i" ) then
	                        if ($?prompt) then
	                              source "$i"
	                        else
	                              source "$i" >& /dev/null
	                        endif
                endif
        end
        unset i nonomatch
endif