#GREP WITH REGULAR EXPRESSION SERIAL#

Note that the regular expression would match the search string no matter where on the line it occurred: the beginning, end, or middle of the word or line. The previous section used an exact match regular expression on a file. Using cat as the regular expression to search the previous file returns the following matches: cat Suppose a user is looking through the following file looking for all occurrences of the pattern cat: catĬat is an exact match of a c, followed by an a, followed by a t with no other characters in between. An exact match is when the characters in the regular expression match the type and order in the data that is being searched. The simplest regular expression is an exact match. This section looks at the syntax used when creating regular expressions, as well as showing some regular expression examples Describing a Simple Regular Expression Regular expressions are a language of their own, which means they have their own syntax and rules.

Programming languages such as Perl, Python, and C can all use regular expressions when using pattern matching criteria. The vim, grep, and less commands can all use regular expressions. rw-r-r- 1 root root 8287 Oct 26 17:57 07.pemīut if I do not use -l on ls, then it returns the proper results that I am looking for, so clearly my regex is correct: ls keys/ | grep -E '*2.Regular expressions provide a pattern matching mechanism that facilitates finding specific content. rw-r-r- 1 root root 8287 Oct 26 17:57 linuxtest-client2.crt

#GREP WITH REGULAR EXPRESSION SERIAL#

rw-r-r- 1 root root 3 Oct 26 17:57 serial rw-r-r- 1 root root 1793 Oct 26 17:57 linuxtest-client2.csr rw- 1 root root 3394 Oct 26 17:57 linuxtest-client2.key rw-r-r- 1 root root 8287 Oct 23 20:54 linuxtest-client1.crt

rw-r-r- 1 root root 3 Oct 23 20:54 serial.old rw-r-r- 1 root root 1793 Oct 23 20:54 linuxtest-client1.csr rw- 1 root root 3394 Oct 23 20:54 linuxtest-client1.key rw-r-r- 1 root root 8264 Oct 23 19:48 removemetest.crt rw-r-r- 1 root root 1785 Oct 23 19:48 removemetest.csr rw- 1 root root 3394 Oct 23 19:48 removemetest.key Why are the file sizes being trigger by this grep when there is no period after them?: ls -ltr keys/ | grep -E '*2.*'

This causes results to be returned that have a '2' in the file size, date, and time. When I grep for the middle portion of the filename, '2.', it also returns lines that contain '2' in addition to '2.' when using ls -l with it. This includes multiple file extensions (csr, crt, key). Using grep to search for all files linuxtest-client2.

Grep with regular expression