如何从文件中的匹配行中提取子字符串？

Question

I use:

cat display.txt | sed -e 's/...\(.*\).../\1/g' 

to get string between("..."). But, it gives me this result which is full content of the file. How can I extract just "hhgggeeee" from this?

= New Index: 98:4F:EE:06:0B:03 (BR/EDR,UART,hci0)               
[hci0] 0.595705 > ACL Data RX: Handle 12 flags 0x02 dlen 19                    
[hci0] 11.420307 Channel: 64 len 15 [PSM 0 mode 0] {chan 0}     
1b ef 17 68 68 67 67 67 65 65 65 65 0d 0a 8f 
...hhgggeeee... > HCI Event: Mode Change (0x14) plen 6 [hci0] 11.923905
Status: Success (0x00) Handle: 12 Mode: Active (0x00)
Interval: 0.000 msec (0x0000)

Answer 1

You can use a perl one liner for this:

perl -lne 'print $1 if /^\.\.\.(.*)\.\.\./' display.txt

For your file, it outputs:

hhgggeeee

Answer 2

You can use a sed command. Try the below command.

cat dis.txt|sed -n 's/\.\.\.\([^\.]\+\)\.\.\..*/\1/gp' 

Or use can use the grep command also.

cat dis.txt|grep -o '\.\.\.\([^\.]\+\)\.\.\.'

The both are gives the same output. The output is

hhgggeeee

Answer 3

$ sed -n 's/.*\.\{3\}\(.*\)\.\{3\}.*/\1/p' file
hhgggeeee