Extract substring according to regexp with sed or grep












4















In a (BSD) UNIX environment, I would like to capture a specific substring using a regular expression.



Assume that the dmesg command output would include the following line: 



pass2: <Marvell Console 1.01> Removable Processor SCSI device


I would like to capture the text between the < and > characters, like



dmesg | <sed command>



should output:



Marvell Console 1.01


However, it should not output anything if the regex does not match. Many solutions including sed -e 's/$regex/1/ will output the whole input if no match is found, which is not what i want.



The corresponding regexp could be:
regex="^pass2: <(.*)>"



How would i properly do a regex match using sed or grep? Note that the grep -P option is unavailable in my BSD UNIX distribution. The sed -E option is available, however.






sed grep regular-expression







share|improve this question























  • It's possibly better to parse the output of camcontrol devlist than the output of dmesg.

    – JdeBP
    yesterday
















4















In a (BSD) UNIX environment, I would like to capture a specific substring using a regular expression.



Assume that the dmesg command output would include the following line: 



pass2: <Marvell Console 1.01> Removable Processor SCSI device


I would like to capture the text between the < and > characters, like



dmesg | <sed command>



should output:



Marvell Console 1.01


However, it should not output anything if the regex does not match. Many solutions including sed -e 's/$regex/1/ will output the whole input if no match is found, which is not what i want.



The corresponding regexp could be:
regex="^pass2: <(.*)>"



How would i properly do a regex match using sed or grep? Note that the grep -P option is unavailable in my BSD UNIX distribution. The sed -E option is available, however.






sed grep regular-expression







share|improve this question























  • It's possibly better to parse the output of camcontrol devlist than the output of dmesg.

    – JdeBP
    yesterday














4












4








4








In a (BSD) UNIX environment, I would like to capture a specific substring using a regular expression.



Assume that the dmesg command output would include the following line: 



pass2: <Marvell Console 1.01> Removable Processor SCSI device


I would like to capture the text between the < and > characters, like



dmesg | <sed command>



should output:



Marvell Console 1.01


However, it should not output anything if the regex does not match. Many solutions including sed -e 's/$regex/1/ will output the whole input if no match is found, which is not what i want.



The corresponding regexp could be:
regex="^pass2: <(.*)>"



How would i properly do a regex match using sed or grep? Note that the grep -P option is unavailable in my BSD UNIX distribution. The sed -E option is available, however.






sed grep regular-expression







share|improve this question














In a (BSD) UNIX environment, I would like to capture a specific substring using a regular expression.



Assume that the dmesg command output would include the following line: 



pass2: <Marvell Console 1.01> Removable Processor SCSI device


I would like to capture the text between the < and > characters, like



dmesg | <sed command>



should output:



Marvell Console 1.01


However, it should not output anything if the regex does not match. Many solutions including sed -e 's/$regex/1/ will output the whole input if no match is found, which is not what i want.



The corresponding regexp could be:
regex="^pass2: <(.*)>"



How would i properly do a regex match using sed or grep? Note that the grep -P option is unavailable in my BSD UNIX distribution. The sed -E option is available, however.






sed grep regular-expression




sed grep regular-expression






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked yesterday









SteinerSteiner

788




788













  • It's possibly better to parse the output of camcontrol devlist than the output of dmesg.

    – JdeBP
    yesterday



















  • It's possibly better to parse the output of camcontrol devlist than the output of dmesg.

    – JdeBP
    yesterday

















It's possibly better to parse the output of camcontrol devlist than the output of dmesg.

– JdeBP
yesterday





It's possibly better to parse the output of camcontrol devlist than the output of dmesg.

– JdeBP
yesterday










3 Answers
3






active

oldest

votes


















7














Try this,



sed -nE 's/^pass2:.*<(.*)>.*$/1/p'


Or POSIXly (-E has not made it to the POSIX standard yet as of 2019):



sed -n 's/^pass2:.*<(.*)>.*$/1/p'


Output:



$ printf '%sn' 'pass2: <Marvell Console 1.01> Removable Processor SCSI device' | sed -nE 's/^pass2:.*<(.*)>.*$/1/p'

Marvell Console 1.01


This will only print the last occurrence of <...> for each line.






share|improve this answer


























  • This works for me, with both the -n parameter and the /p suffix inside the regex. Full command i used: dmesg | sed -nE 's/^pass2: <(.*)>.*$/1/p

    – Steiner
    yesterday






  • 1





    Why not use <([^>]+)>? I.e. not-> one-or-more times

    – Rich
    yesterday






  • 1





    sed regex is per default non-greedy, so it's not necessary here. But it would work, too.

    – RoVo
    13 hours ago



















5














How about -o under grep to just print the matching part? We still need to remove the <>, though, but tr works there.



dmesg |egrep -o "<([a-zA-Z.0-9 ]+)>" |tr -d "<>"

Marvell Console 1.01





share|improve this answer

































    2














    I tried below 3 methods by using sed, awk and python



    sed command



    echo "pass2: <Marvell Console 1.01> Removable Processor SCSI device" | sed "s/.*<//g"|sed "s/>.*//g"


    output



    Marvell Console 1.01


    awk command



    echo "pass2: <Marvell Console 1.01> Removable Processor SCSI device" | awk -F "[<>]" '{print $2}'


    output



    Marvell Console 1.01


    python



    #!/usr/bin/python
    
import re
    
h=
    
k=open('l.txt','r')
    
l=k.readlines()
    
for i in l:
    
    o=i.split(' ')
    
    for i in o[1:4]:
    
        h.append(i)
    
print (" ".join(h)).replace('>','').replace('<','')


    output



    Marvell Console 1.01





    share|improve this answer


























    • I was thinking the awk approach too. Should you constrain your print to lines beginning with "pass2:"? The OP didn't provide sufficient detail, but I can imagine that a naive pattern match would not be quite what was wanted.

      – jwm
      20 hours ago











    • Python can read from standard in, though perl specializes in this kind of text processing if you’re moving into higher level scripting languages.

      – D. Ben Knoble
      16 hours ago











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    3 Answers
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    3 Answers
    3






    active

    oldest

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    active

    oldest

    votes






    active

    oldest

    votes









    7














    Try this,



    sed -nE 's/^pass2:.*<(.*)>.*$/1/p'


    Or POSIXly (-E has not made it to the POSIX standard yet as of 2019):



    sed -n 's/^pass2:.*<(.*)>.*$/1/p'


    Output:



    $ printf '%sn' 'pass2: <Marvell Console 1.01> Removable Processor SCSI device' | sed -nE 's/^pass2:.*<(.*)>.*$/1/p'
    
Marvell Console 1.01


    This will only print the last occurrence of <...> for each line.






    share|improve this answer


























    • This works for me, with both the -n parameter and the /p suffix inside the regex. Full command i used: dmesg | sed -nE 's/^pass2: <(.*)>.*$/1/p

      – Steiner
      yesterday






    • 1





      Why not use <([^>]+)>? I.e. not-> one-or-more times

      – Rich
      yesterday






    • 1





      sed regex is per default non-greedy, so it's not necessary here. But it would work, too.

      – RoVo
      13 hours ago
















    7














    Try this,



    sed -nE 's/^pass2:.*<(.*)>.*$/1/p'


    Or POSIXly (-E has not made it to the POSIX standard yet as of 2019):



    sed -n 's/^pass2:.*<(.*)>.*$/1/p'


    Output:



    $ printf '%sn' 'pass2: <Marvell Console 1.01> Removable Processor SCSI device' | sed -nE 's/^pass2:.*<(.*)>.*$/1/p'
    
Marvell Console 1.01


    This will only print the last occurrence of <...> for each line.






    share|improve this answer


























    • This works for me, with both the -n parameter and the /p suffix inside the regex. Full command i used: dmesg | sed -nE 's/^pass2: <(.*)>.*$/1/p

      – Steiner
      yesterday






    • 1





      Why not use <([^>]+)>? I.e. not-> one-or-more times

      – Rich
      yesterday






    • 1





      sed regex is per default non-greedy, so it's not necessary here. But it would work, too.

      – RoVo
      13 hours ago














    7












    7








    7







    Try this,



    sed -nE 's/^pass2:.*<(.*)>.*$/1/p'


    Or POSIXly (-E has not made it to the POSIX standard yet as of 2019):



    sed -n 's/^pass2:.*<(.*)>.*$/1/p'


    Output:



    $ printf '%sn' 'pass2: <Marvell Console 1.01> Removable Processor SCSI device' | sed -nE 's/^pass2:.*<(.*)>.*$/1/p'
    
Marvell Console 1.01


    This will only print the last occurrence of <...> for each line.






    share|improve this answer















    Try this,



    sed -nE 's/^pass2:.*<(.*)>.*$/1/p'


    Or POSIXly (-E has not made it to the POSIX standard yet as of 2019):



    sed -n 's/^pass2:.*<(.*)>.*$/1/p'


    Output:



    $ printf '%sn' 'pass2: <Marvell Console 1.01> Removable Processor SCSI device' | sed -nE 's/^pass2:.*<(.*)>.*$/1/p'
    
Marvell Console 1.01


    This will only print the last occurrence of <...> for each line.







    share|improve this answer














    share|improve this answer



    share|improve this answer








    edited yesterday









    Stéphane Chazelas

    310k57586945




    310k57586945










    answered yesterday









    RoVoRoVo

    3,332317




    3,332317













    • This works for me, with both the -n parameter and the /p suffix inside the regex. Full command i used: dmesg | sed -nE 's/^pass2: <(.*)>.*$/1/p

      – Steiner
      yesterday






    • 1





      Why not use <([^>]+)>? I.e. not-> one-or-more times

      – Rich
      yesterday






    • 1





      sed regex is per default non-greedy, so it's not necessary here. But it would work, too.

      – RoVo
      13 hours ago



















    • This works for me, with both the -n parameter and the /p suffix inside the regex. Full command i used: dmesg | sed -nE 's/^pass2: <(.*)>.*$/1/p

      – Steiner
      yesterday






    • 1





      Why not use <([^>]+)>? I.e. not-> one-or-more times

      – Rich
      yesterday






    • 1





      sed regex is per default non-greedy, so it's not necessary here. But it would work, too.

      – RoVo
      13 hours ago

















    This works for me, with both the -n parameter and the /p suffix inside the regex. Full command i used: dmesg | sed -nE 's/^pass2: <(.*)>.*$/1/p

    – Steiner
    yesterday





    This works for me, with both the -n parameter and the /p suffix inside the regex. Full command i used: dmesg | sed -nE 's/^pass2: <(.*)>.*$/1/p

    – Steiner
    yesterday




    1




    1





    Why not use <([^>]+)>? I.e. not-> one-or-more times

    – Rich
    yesterday





    Why not use <([^>]+)>? I.e. not-> one-or-more times

    – Rich
    yesterday




    1




    1





    sed regex is per default non-greedy, so it's not necessary here. But it would work, too.

    – RoVo
    13 hours ago





    sed regex is per default non-greedy, so it's not necessary here. But it would work, too.

    – RoVo
    13 hours ago













    5














    How about -o under grep to just print the matching part? We still need to remove the <>, though, but tr works there.



    dmesg |egrep -o "<([a-zA-Z.0-9 ]+)>" |tr -d "<>"
    
Marvell Console 1.01





    share|improve this answer






























      5














      How about -o under grep to just print the matching part? We still need to remove the <>, though, but tr works there.



      dmesg |egrep -o "<([a-zA-Z.0-9 ]+)>" |tr -d "<>"
      
Marvell Console 1.01





      share|improve this answer




























        5












        5








        5







        How about -o under grep to just print the matching part? We still need to remove the <>, though, but tr works there.



        dmesg |egrep -o "<([a-zA-Z.0-9 ]+)>" |tr -d "<>"
        
Marvell Console 1.01





        share|improve this answer















        How about -o under grep to just print the matching part? We still need to remove the <>, though, but tr works there.



        dmesg |egrep -o "<([a-zA-Z.0-9 ]+)>" |tr -d "<>"
        
Marvell Console 1.01






        share|improve this answer














        share|improve this answer



        share|improve this answer








        edited yesterday









        ilkkachu

        61.9k10101178




        61.9k10101178










        answered yesterday









        Radek RadekRadek Radek

        1014




        1014























            2














            I tried below 3 methods by using sed, awk and python



            sed command



            echo "pass2: <Marvell Console 1.01> Removable Processor SCSI device" | sed "s/.*<//g"|sed "s/>.*//g"


            output



            Marvell Console 1.01


            awk command



            echo "pass2: <Marvell Console 1.01> Removable Processor SCSI device" | awk -F "[<>]" '{print $2}'


            output



            Marvell Console 1.01


            python



            #!/usr/bin/python
            
import re
            
h=
            
k=open('l.txt','r')
            
l=k.readlines()
            
for i in l:
            
    o=i.split(' ')
            
    for i in o[1:4]:
            
        h.append(i)
            
print (" ".join(h)).replace('>','').replace('<','')


            output



            Marvell Console 1.01





            share|improve this answer


























            • I was thinking the awk approach too. Should you constrain your print to lines beginning with "pass2:"? The OP didn't provide sufficient detail, but I can imagine that a naive pattern match would not be quite what was wanted.

              – jwm
              20 hours ago











            • Python can read from standard in, though perl specializes in this kind of text processing if you’re moving into higher level scripting languages.

              – D. Ben Knoble
              16 hours ago
















            2














            I tried below 3 methods by using sed, awk and python



            sed command



            echo "pass2: <Marvell Console 1.01> Removable Processor SCSI device" | sed "s/.*<//g"|sed "s/>.*//g"


            output



            Marvell Console 1.01


            awk command



            echo "pass2: <Marvell Console 1.01> Removable Processor SCSI device" | awk -F "[<>]" '{print $2}'


            output



            Marvell Console 1.01


            python



            #!/usr/bin/python
            
import re
            
h=
            
k=open('l.txt','r')
            
l=k.readlines()
            
for i in l:
            
    o=i.split(' ')
            
    for i in o[1:4]:
            
        h.append(i)
            
print (" ".join(h)).replace('>','').replace('<','')


            output



            Marvell Console 1.01





            share|improve this answer


























            • I was thinking the awk approach too. Should you constrain your print to lines beginning with "pass2:"? The OP didn't provide sufficient detail, but I can imagine that a naive pattern match would not be quite what was wanted.

              – jwm
              20 hours ago











            • Python can read from standard in, though perl specializes in this kind of text processing if you’re moving into higher level scripting languages.

              – D. Ben Knoble
              16 hours ago














            2












            2








            2







            I tried below 3 methods by using sed, awk and python



            sed command



            echo "pass2: <Marvell Console 1.01> Removable Processor SCSI device" | sed "s/.*<//g"|sed "s/>.*//g"


            output



            Marvell Console 1.01


            awk command



            echo "pass2: <Marvell Console 1.01> Removable Processor SCSI device" | awk -F "[<>]" '{print $2}'


            output



            Marvell Console 1.01


            python



            #!/usr/bin/python
            
import re
            
h=
            
k=open('l.txt','r')
            
l=k.readlines()
            
for i in l:
            
    o=i.split(' ')
            
    for i in o[1:4]:
            
        h.append(i)
            
print (" ".join(h)).replace('>','').replace('<','')


            output



            Marvell Console 1.01





            share|improve this answer















            I tried below 3 methods by using sed, awk and python



            sed command



            echo "pass2: <Marvell Console 1.01> Removable Processor SCSI device" | sed "s/.*<//g"|sed "s/>.*//g"


            output



            Marvell Console 1.01


            awk command



            echo "pass2: <Marvell Console 1.01> Removable Processor SCSI device" | awk -F "[<>]" '{print $2}'


            output



            Marvell Console 1.01


            python



            #!/usr/bin/python
            
import re
            
h=
            
k=open('l.txt','r')
            
l=k.readlines()
            
for i in l:
            
    o=i.split(' ')
            
    for i in o[1:4]:
            
        h.append(i)
            
print (" ".join(h)).replace('>','').replace('<','')


            output



            Marvell Console 1.01






            share|improve this answer














            share|improve this answer



            share|improve this answer








            edited yesterday









            ilkkachu

            61.9k10101178




            61.9k10101178










            answered yesterday









            Praveen Kumar BSPraveen Kumar BS

            1,6351311




            1,6351311













            • I was thinking the awk approach too. Should you constrain your print to lines beginning with "pass2:"? The OP didn't provide sufficient detail, but I can imagine that a naive pattern match would not be quite what was wanted.

              – jwm
              20 hours ago











            • Python can read from standard in, though perl specializes in this kind of text processing if you’re moving into higher level scripting languages.

              – D. Ben Knoble
              16 hours ago



















            • I was thinking the awk approach too. Should you constrain your print to lines beginning with "pass2:"? The OP didn't provide sufficient detail, but I can imagine that a naive pattern match would not be quite what was wanted.

              – jwm
              20 hours ago











            • Python can read from standard in, though perl specializes in this kind of text processing if you’re moving into higher level scripting languages.

              – D. Ben Knoble
              16 hours ago

















            I was thinking the awk approach too. Should you constrain your print to lines beginning with "pass2:"? The OP didn't provide sufficient detail, but I can imagine that a naive pattern match would not be quite what was wanted.

            – jwm
            20 hours ago





            I was thinking the awk approach too. Should you constrain your print to lines beginning with "pass2:"? The OP didn't provide sufficient detail, but I can imagine that a naive pattern match would not be quite what was wanted.

            – jwm
            20 hours ago













            Python can read from standard in, though perl specializes in this kind of text processing if you’re moving into higher level scripting languages.

            – D. Ben Knoble
            16 hours ago





            Python can read from standard in, though perl specializes in this kind of text processing if you’re moving into higher level scripting languages.

            – D. Ben Knoble
            16 hours ago


















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              本文介紹的是國際性音樂電視頻道Channel [V]的主條目。關於在臺灣地區前稱Channel [V]的子電視頻道，請見「 FOX (台灣頻道) 」。 body.skin-minerva .mw-parser-output table.infobox caption{text-align:center} Channel [V] Channel [V] 所有者 星空傳媒 福斯傳媒集團 星空華文傳媒（中国大陆频道） 开播日期 1991年9月15日 口号 全球最強華語音樂頻道；亞洲第一音樂頻道 播出地区 亞洲各地 旧称 衛視音樂台 取代者 [V] by FOX (東南亞和中東國家版本) 姊妹频道 星空衛視 收看方法 有线电视   澳門澳門有線電視 [V]國際頻道：73頻道 [V]中國頻道：74頻道   中国深圳天威视讯 [V]中國頻道：尚未定頻   中国南京数字电视 [V]中國頻道：91頻道   中国中国大陸数字电视 [V]中國頻道：随地区而变 宽带电视   香港now寬頻電視 [V]國際頻道：534頻道 臺灣中華電信MOD [V]國際娛樂頻道HD：151頻道   新加坡Mio TV [V]國際娛樂頻道HD：352頻道 [V]中國頻道：547頻道 Channel [V] 是一個國際性的音樂電視頻道，隸屬於星空傳媒，在東亞、東南亞、南亞、中東地區等地多個國家播放。該頻道主要播放英文主流音樂和一些區域性語言的歌曲，其中在台灣與中國大陸主要播放華語流行音樂。2010年8月星空傳媒把中国大陆頻道控股權易手予上海市人民政府牽頭成立的華人文化產業投資基金 [1] 。 目录 1 V的含義 2 Channel [V]國際頻道 3 Channel [V]臺灣頻道 4 Channel [V]中國頻道 5 其它的Channel [V]頻道 6 参见 7 參考資料 8 外部链接 V的含義 官方並無提供字母 V 的確切含義，以下是流傳的說法： 最廣泛的說法是V代表胜利（victory）...
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