linux字符串提取數(shù)字

# cat /proc/meminfo |grep -w "MemTotal"

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MemTotal:? ? ? 32781228 kB

使用tr命令截取字符串

# cat /proc/meminfo |grep -w "MemTotal" | tr -cd "[0-9]"

32781228

linux有什么命令可以提取指定的字符串

1. 例子

提取字符串以下字符串 error: 與 : 之間的子字符串。并消除空格。

"src/network/misc/nv_net_udp.c:17:?fatal?error:?nv_net_tools.h:?No?such?file?or?directory"1

2. 命令

echo?"src/network/misc/nv_net_udp.c:17:?fatal?error:?nv_net_tools.h:?No?such?file?or?directory"?|?sed?-r?'s/.*error\:(.*)\:.*/\1/'?|?sed?s/[[:space:]]//g1

該命令涉及 sed 命令的’反向引用’章節(jié), \1 代表 (.*)

3. 結果

nv_net_tools.h1

4. 拓展 ： 解決編譯錯誤

leon$??make?clean??make?all?arm-hisiv100nptl-linux-gcc?-c?-fPIC?-Wall?-g?-ggdb?-O0?-DHI3518_CHIP?-DLINUX?-I./src/include?-I./src/include/common?-I./src/include/camera?-I./src/include/conf?-I./src/include/log?-I./src/include/network?-I./src/include/upnp?-I/home/leon/nvc/arm-hisiv100nptl-linux/include?src/common/nv_conf.c?-o?build/objs/hi3518/src/common/nv_conf.o/*省略中間部分*/arm-hisiv100nptl-linux-gcc?-c?-fPIC?-Wall?-g?-ggdb?-O0?-DHI3518_CHIP?-DLINUX?-I./src/include?-I./src/include/common?-I./src/include/camera?-I./src/include/conf?-I./src/include/log?-I./src/include/network?-I./src/include/upnp?-I/home/leon/nvc/arm-hisiv100nptl-linux/include?src/network/misc/nv_net_udp.c?-o?build/objs/hi3518/src/network/misc/nv_net_udp.o

src/network/misc/nv_net_udp.c:17:?fatal?error:?nv_net_tools.h:?No?such?file?or?directory

compilation?terminated.make:?***?[build/objs/hi3518/src/network/misc/nv_net_udp.o]?Error?112345678

note: 在以上編譯過程中我們發(fā)現(xiàn),編譯器提示說找不到nv_net_tools.h文件，而現(xiàn)實中我們也不需要這個文件的包含了，需要刪除包含nv_net_tools.h 文件中的該行代碼。

5.字符串提取 (命令行)

目標字符串

"from":"0802070975","to":"0802071013","url":"","md5":"ace4b34383f964442a591559d0afb296","level":0?12

需要提取 from , to, url , md5, level 等5個關鍵字后面的內容。

//提取 from ?內容echo

"from":"0802070975","to":"0802071013","url":"","md5":"ace4b34383f964442a591559d0afb296","level":0?|??sed?"s/.*from:\(.*\)/\1/"?|??cut?-d?','?-f1

//提取 to 內容echo

"from":"0802070975","to":"0802071013","url":"","md5":"ace4b34383f964442a591559d0afb296","level":0?|??sed?"s/.*to:\(.*\)/\1/"?|??cut?-d?','?-f1

//提取 url ?內容echo

"from":"0802070975","to":"0802071013","url":"","md5":"ace4b34383f964442a591559d0afb296","level":0?|??sed?"s/.*url:\(.*\)/\1/"?|??cut?-d?','?-f1

//提取 md5 內容echo

"from":"0802070975","to":"0802071013","url":"","md5":"ace4b34383f964442a591559d0afb296","level":0?|??sed?"s/.*md5:\(.*\)/\1/"?|??cut?-d?','?-f1

//提取 level 內容echo

"from":"0802070975","to":"0802071013","url":"","md5":"ace4b34383f964442a591559d0afb296","level":0?|??sed?"s/.*level:\(.*\)/\1/"?|??cut?-d?','?-f112345678910111213141516

6.字符串提取 (腳本文件)

ret_val="\"from\":\"0804020982\",\"to\":\"0804020998\",\"url\":\"\",\"md5\":\"408d261924e6c271200fdf14d3a230cc\",\"level\":0"

echo?ret_val?is?:?[?$ret_val?]from="$(echo?$ret_val?|?sed?'s/.*from\"\:\(.*\)/\1/'?|??cut?-d?','?-f1?|??sed?'s/"http://g')"

echo?from:?$from

to="$(echo?$ret_val?|?sed?'s/.*to\"\:\(.*\)/\1/'?|??cut?-d?','?-f1?|??sed?'s/"http://g')"

echo?to:?$to

url="$(echo?$ret_val?|?sed?'s/.*url\"\:\(.*\)/\1/'?|??cut?-d?','?-f1?|??sed?'s/"http://g')"

echo?url:?$url

md5="$(echo?$ret_val?|?sed?'s/.*md5\"\:\(.*\)/\1/'?|??cut?-d?','?-f1?|?sed?'s/"http://g')"

echo?md5:?$md5

level="$(echo?$ret_val?|?sed?'s/.*level\"\:\(.*\)/\1/'?|??cut?-d?','?-f1?|?sed?'s/"http://g')"

echo?level:?$level12345678910111213141516171819

執(zhí)行結果：

ret_val?is?:?[?"from":"0804020982","to":"0804020998","url":"","md5":"408d261924e6c271200fdf14d3a230cc","level":0?]

from:?0804020982

to:?0804020998

url:?:?408d261924e6c271200fdf14d3a230cc

level:?0

I.總結

要注意命令行執(zhí)行，與腳本文件執(zhí)行之間的差異性。

linux 中如何截取2個字符串中間的字符？

可以用awk、sed、tr、perl都能實現(xiàn)

set s = '"stratum":{"accepted_shares":1,"algorithm"'

set a = `echo $s | awk -F '["/:]' '{print $4}'`