What is the difference between grep -e and grep -E option?
grep -e PATTERN unless, as stated in an earlier Answer and in the man pages, there are multiple search patterns, or to protect a pattern beginning with a hyphen (-).
linux - What is the point of "grep -q" - Stack Overflow
May 16, 2019 · Moreover, this is a lot faster than a regular grep invocation, since it can exit immediately when the first match is found, rather than needing to unconditionally read (and …
How to run grep with multiple AND patterns? - Unix & Linux Stack …
Mar 25, 2016 · I would like to get the multi pattern match with implicit AND between patterns, i.e. equivalent to running several greps in a sequence: grep pattern1 | grep pattern2 | ... So how to …
UNIX grep command (grep -v grep) - Stack Overflow
Apr 5, 2015 · 11 grep when used with ps -ef also outputs the grep used for filtering the output of ps -ef. grep -v grep means that do not include the grep used for filtering in the command …
Using the star sign in grep - Stack Overflow
Jul 6, 2016 · grep itself doesn't support wildcards on most platforms. You have to use egrep to use wildcards. Shells have a different syntax. "*" in the shell is <any string>. In egrep it's an …
What's the difference between grep -r and -R - Stack Overflow
Mar 31, 2014 · In the man page: -r Read all files under each directory, recursively, following symbolic links only if they are on the command line. what exactly does "being on the command …
grepping using the result of previous grep - Stack Overflow
Sep 20, 2015 · Is there a way to perform a grep based on the results of a previous grep, rather than just piping multiple greps into each other. For example, say I have the log file output …
regex - How can I exclude one word with grep? - Stack Overflow
Dec 27, 2010 · Here grep will try to list all the occurrences of 'wanted_pattern' in all the files from within currently directory and pass it to second grep to filter out the 'unwanted_pattern'. '|' - …
Grep: how to add an "OR" condition? - Unix & Linux Stack Exchange
Dec 1, 2011 · How can I introduce a conditional OR into grep? Something like, grepping a file's type for (JPEG OR JPG), and then sending only those files into the photos folder. For …
How can I grep for this or that (2 things) in a file?
grep understands three different versions of regular expression syntax: “basic,” “extended” and “perl.” In GNU grep, there is no difference in available functionality between basic and …