h9 - 台部落

Filename Wildcards

* acts as a match for any number and sequence of characters

? acts as a match for any single character

$ ls -d v* directory

$ ls *a contents

$ echo *

$ echo v*

$ echo 'hello world'

Advanced Filename Wildcards

character range:

$ ls -ld [abkost]*

$ ls -ld [a-z]*

search for all files that contain a single digit, dot, or underscore in the name

$ ls *[0-9._]*

Creating Sophisticated Regular Expressions

Summary of regular-expression notation.

Notation Meaning

c Matches the character c

/c Forces c to be read as the letter c, not as another meaning the character might have

^ Beginning of the line

$ End of the line

. Any single character

[xy] Any single character in the set specified

[^xy] Any single character not in the set specified

c* Zero or more occurrences of character c

$ grep miscall /etc/passwd

$ grep ^miscall /etc/passwd

$ grep "^miscall[a-z]" /etc/passwd

$ grep '^miscall[^a-z]' /etc/passwd

$ grep z* /etc/passwd|head

is identical to

$ head /etc/passwd

$ grep ':$' /etc/passwd

$ grep '$100*' * */*

* expands your search beyond files in the current directory

*/* expands your search to all files contained one directory below the current point

$ grep '. ' file

$ grep '/. ' file

Searching Files Using grep

The most helpful grep flags.

Flag Function

-c List a count of matching lines only.

-i Ignore the case of the letters in the pattern.

-l List filenames of files that match the specified pattern only.

-n Include line numbers.

For Complex Expressions, Try egrep

Regular expression notation for egrep.

Notation Meaning

c Matches the character c

/c Forces c to be read as the letter c, not as another meaning the character might have

^ Beginning of the line

$ End of the line

. Any single character

[xy] Any single character in the set specified

[^xy] Any single character not in the set specified

c* Zero or more occurrences of character c

c+ One or more occurrences of character c

c? Zero or one occurrences of character c

a|b Either a or b

(a) Regular expression

$ egrep '(z|q)' /etc/passwd | head

$ egrep '(^[a-zA-Z]|:wi)' /etc/printcap | head

Any time you want to look for lines that contain more than a single pattern, egrep is the best command to use.

Searching for Multiple Patterns at Once with fgrep

Changing Things En Route with sed

The general format of the substitution command is: s/old/new/flags, where old and new are the patterns you’re working with, s is the abbreviation for the substitute command, and the two most helpful flags are：

g (to replace all occurrences globally on each line)

n (to tell sed to replace only the first n occurrences of the pattern).

$ grep taylor /etc/passwd | sed -e 's/:/ /'

taylorj ?:1048:1375:James Taylor:/users/taylorj:/bin/csh

mtaylor ?:769:1375:Mary Taylor:/users/mtaylor:/usr/local/bin/tcsh

dataylor ?:375:518:Dave Taylor,,,,:/users/dataylor:/usr/local/lib/msh

taylorjr ?:203:1022:James Taylor:/users/taylorjr:/bin/csh

taylorrj ?:662:1042:Robert Taylor:/users/taylorrj:/bin/csh

taylorm ?:869:1508:Melanie Taylor:/users/taylorm:/bin/csh

taylor ?:1989:1412:Dave Taylor:/users/taylor:/bin/csh

$ grep taylor /etc/passwd | sed -e 's/:/ /g'

taylorj ? 1048 1375 James Taylor /users/taylorj /bin/csh

mtaylor ? 769 1375 Mary Taylor /users/mtaylor /usr/local/bin/tcsh

dataylor ? 375 518 Dave Taylor /users/dataylor /usr/local/lib/msh

taylorjr ? 203 1022 James Taylor /users/taylorjr /bin/csh

taylorrj ? 662 1042 Robert Taylor /users/taylorrj /bin/csh

taylorm ? 869 1508 Melanie Taylor /users/taylorm /bin/csh

taylor ? 1989 1412 Dave Taylor /users/taylor /bin/csh

$ grep taylor /etc/passwd | sed -e 's/Taylor/Tailor/g'

taylorj:?:1048:1375:James Tailor:/users/taylorj:/bin/csh

mtaylor:?:769:1375:Mary Tailor:/users/mtaylor:/usr/local/bin/tcsh

dataylor:?:375:518:Dave Tailor:/users/dataylor:/usr/local/lib/msh

taylorjr:?:203:1022:James Tailor:/users/taylorjr:/bin/csh

taylorrj:?:662:1042:Robert Tailor:/users/taylorrj:/bin/csh

taylorm:?:869:1508:Melanie Tailor:/users/taylorm:/bin/csh

taylor:?:1989:1412:Dave Tailor:/users/taylor:/bin/csh

$ grep taylor /etc/passwd | sed -e 's/Taylor/Tailor/g;s/:/ /g'

$ who

strawmye ttyAc Nov 21 19:01

eiyo ttyAd Nov 21 17:40

tzhen ttyAg Nov 21 19:13

kmkernek ttyAh Nov 17 23:22

macedot ttyAj Nov 21 20:41

rpm ttyAk Nov 21 20:40

ypchen ttyAl Nov 21 18:20

kodak ttyAm Nov 21 20:43

$ who | sed 's/tty/On Device /;s/Nov/Logged in November/'

strawmye On Device Ac Logged in November 21 19:01

eiyo On Device Ad Logged in November 21 17:40

tzhen On Device Ag Logged in November 21 19:13

kmkernek On Device Ah Logged in November 17 23:22

macedot On Device Aj Logged in November 21 20:41

rpm On Device Ak Logged in November 21 20:40

ypchen On Device Al Logged in November 21 18:20

kodak On Device Am Logged in November 21 20:43

he sed command also can be used to delete lines in the stream as it passes. The simplest version is to specify only the command:

$ who | sed 'd'

$ who | sed '1d'

eiyo ttyAd Nov 21 17:40

tzhen ttyAg Nov 21 19:13

kmkernek ttyAh Nov 17 23:22

macedot ttyAj Nov 21 20:41

rpm ttyAk Nov 21 20:40

ypchen ttyAl Nov 21 18:20

kodak ttyAm Nov 21 20:43

$ who | sed '1,3d'

macedot ttyAj Nov 21 20:41

rpm ttyAk Nov 21 20:40

ypchen ttyAl Nov 21 18:20

kodak ttyAm Nov 21 20:43

$ who | head -15 | sed '/eiyo/,/rpm/d'

root console Nov 9 07:31

rick ttyAa Nov 21 20:58

brunnert ttyAb Nov 21 20:56

ypchen ttyAl Nov 21 18:20

kodak ttyAm Nov 21 20:43

wh ttyAn Nov 21 20:33

klingham ttyAp Nov 21 19:55

linet2 ttyAq Nov 21 20:17

mdps ttyAr Nov 21 20:11

$ who | sed '1,/kmkernek/d'

macedot ttyAj Nov 21 20:41

rpm ttyAk Nov 21 20:40

ypchen ttyAl Nov 21 18:20

kodak ttyAm Nov 21 20:43

$ cat testme

Archives/ OWL/ keylime.pie

InfoWorld/ bin/ src/