{"id":101,"date":"2022-03-28T21:50:39","date_gmt":"2022-03-29T01:50:39","guid":{"rendered":"http:\/\/triosdevelopers.com\/J.Smith\/rjeffsmith.ca\/wordpress\/?p=101"},"modified":"2024-10-11T09:30:03","modified_gmt":"2024-10-11T13:30:03","slug":"grep-cheat-sheet","status":"publish","type":"post","link":"https:\/\/triosdevelopers.com\/J.Smith\/rjeffsmith.ca\/wordpress\/?p=101","title":{"rendered":"grep cheat sheet"},"content":{"rendered":"\n
\n
Basics<\/strong><\/td><\/tr>
grep [pattern] FILE<\/td>
<\/td><\/tr>
grep ‘^[A,E].*o’ f.txt<\/td>Find a string starting with A or E and ending in o<\/td><\/tr>
grep -f pat.txt f.txt<\/td>Scan f.txt, using contents of pat.txt as regex<\/td><\/tr>
grep -i Gnu f.txt<\/td>Find “gnu” in f.txt, ignoring capitalization<\/td><\/tr>
grep -v gnu f.txt<\/td>Find all lines not containing “gnu” (invert match)<\/td><\/tr>
grep -w ‘a.*o’ f.txt<\/td>Find whole word matches only, ignoring substrings<\/td><\/tr>
grep -x ‘a.*o’ f.txt<\/td>Find whole line matches only, as in ^(a.*o)$<\/td><\/tr>

Output<\/strong><\/td><\/tr>
-c<\/td>Print only the number of lines containing a match<\/td><\/tr>
–colo[u]r<\/td>Display matches in color<\/td><\/tr>
-l<\/td>Print the names of files with matches<\/td><\/tr>
-L<\/td>Print the names of files searched that contained no matches<\/td><\/tr>
-o<\/td>Print only the matched part of a line<\/td><\/tr>
-s<\/td>Suppress errors (such as non-existent or unreadable files)<\/td><\/tr>
-A n<\/td>Print n number of lines after a matching line<\/td><\/tr>
-B n<\/td>Print n number of lines before a matching line<\/td><\/tr>
-C n<\/td>Print n number of lines before and after a matching line<\/td><\/tr>

Output prefixes<\/strong><\/td><\/tr>
-b<\/td>Print the byte offset of the match within the input file<\/td><\/tr>
-H<\/td>Print the filename containing a match<\/td><\/tr>
-h<\/td>Do not print the filename containing a match<\/td><\/tr>
-n<\/td>Print the line number of each match<\/td><\/tr>
-T<\/td>Print an initial Tab before matches so that output is neatly aligned<\/td><\/tr>

File and directory selection<\/strong><\/td><\/tr>
-a<\/td>Process a binary file as if it were text<\/td><\/tr>
-D <skip|read><\/td>Skip or read a FIFO, device, or socket<\/td><\/tr>
-d <skip|read|recurse><\/td>Skip, read, or recurse through a directory<\/td><\/tr>
–exclude ‘*.sh’<\/td>Do not search any file with the .sh suffix<\/td><\/tr>
–exclude-from FILE<\/td>Skip any file listed in FILE<\/td><\/tr>
–exclude-dir *foo<\/td>Skip any directory ending in foo<\/td><\/tr>
-r<\/td>When a directory is encountered, search files in it<\/td><\/tr>
-R<\/td>Search directories and follow symlinks<\/td><\/tr>

Variants<\/strong><\/td><\/tr>
-G<\/td>Use basic regex (this is the default)<\/td><\/tr>
-E<\/td>Extended regex<\/td><\/tr>
-F<\/td>Interpret the search pattern as a fixed string, not regex<\/td><\/tr>
-P<\/td>Use Perl regex (PCRE)<\/td><\/tr>

Regular expression<\/strong><\/td><\/tr>
.<\/td>Any single character<\/td><\/tr>
?<\/td>Match preceding item zero or one time<\/td><\/tr>
*<\/td>Match preceding item zero or more times<\/td><\/tr>
+<\/td>Match preceding item one or more times<\/td><\/tr>
{2}<\/td>Match preceding item two times<\/td><\/tr>
{3,}<\/td>Match preceding item three or more times<\/td><\/tr>
{,4}<\/td>Match preceding item at most four times<\/td><\/tr>
{1,5}<\/td>Match preceding item at least once, but no more than five times<\/td><\/tr>
[A,B]<\/td>Match A or B<\/td><\/tr>
[3-9]<\/td>Match all digits 3 to 9<\/td><\/tr>
^<\/td>Start of a line<\/td><\/tr>
$<\/td>End of a line<\/td><\/tr>
\\s<\/td>Space<\/td><\/tr>
[:alnum:]<\/td>Alphanumeric character<\/td><\/tr>
[:alpha:]<\/td>Alphabetic character<\/td><\/tr>
[:digit:]<\/td>Digits 0 through 9<\/td><\/tr>
[:punct:]<\/td>Punctuation<\/td><\/tr>
[:space:]<\/td>Space<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div><\/div>\n","protected":false},"excerpt":{"rendered":"

Basics grep [pattern] FILE grep ‘^[A,E].*o’ f.txt Find a string starting with A or E and ending in o grep -f pat.txt f.txt Scan f.txt, using contents of pat.txt as regex grep -i Gnu f.txt Find “gnu” in f.txt, ignoring capitalization grep -v gnu f.txt Find all lines not containing “gnu” (invert match) grep -w […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[15],"tags":[],"class_list":["post-101","post","type-post","status-publish","format-standard","hentry","category-file-management"],"_links":{"self":[{"href":"https:\/\/triosdevelopers.com\/J.Smith\/rjeffsmith.ca\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/101","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/triosdevelopers.com\/J.Smith\/rjeffsmith.ca\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/triosdevelopers.com\/J.Smith\/rjeffsmith.ca\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/triosdevelopers.com\/J.Smith\/rjeffsmith.ca\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/triosdevelopers.com\/J.Smith\/rjeffsmith.ca\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=101"}],"version-history":[{"count":4,"href":"https:\/\/triosdevelopers.com\/J.Smith\/rjeffsmith.ca\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/101\/revisions"}],"predecessor-version":[{"id":109,"href":"https:\/\/triosdevelopers.com\/J.Smith\/rjeffsmith.ca\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/101\/revisions\/109"}],"wp:attachment":[{"href":"https:\/\/triosdevelopers.com\/J.Smith\/rjeffsmith.ca\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=101"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/triosdevelopers.com\/J.Smith\/rjeffsmith.ca\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=101"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/triosdevelopers.com\/J.Smith\/rjeffsmith.ca\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=101"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}