unstill.blogg.se

s, -no-messages Suppress error messages about nonexistent or unreadable files. Exit immediately with zero status if any match is found, even if an error was detected. q, -quiet, -silent Quiet do not write anything to standard output. o, -only-matching Print only the matched (non-empty) parts of a matching line, with each such part on a separate output line. Option is also used, grep stops after outputting NUM non-matching lines. The -c or -count option is also used, grep does not output a count greater than NUM. When grep stops after NUM matching lines, it outputs any trailing context lines. This enables a calling process to resume a search. Grep ensures that the standard input is positioned to just after the last matching line before exiting, regardless of the presence of trailing context

If the input is standard input from a regular file, and NUM matching lines are output, m NUM, -max-count= NUM Stop reading a file after NUM matching lines. l, -files-with-matches Suppress normal output instead print the name of each input file from which output would normally have been printed. L, -files-without-match Suppress normal output instead print the name of each input file from which no output would normally have been printed. Theĭeprecated environment variable GREP_COLOR is still supported, but its setting does not have priority. The colors are defined by the environment variable GREP_COLORS.

Surround the matched (non-empty) strings, matching lines, context lines, file names, line numbers, byte offsets, and separators (for fields and groups ofĬontext lines) with escape sequences to display them in color on the terminal. With the -v, -invert-match option (see below), count General Output Control -c, -count Suppress normal output instead print a count of matching lines for each input file. x, -line-regexp Select only those matches that exactly match the whole line. Word-constituent characters are letters, digits, and the underscore. Similarly, it must be either at the end of the line or followed by a non-word constituent character. Preceded by a non-word constituent character. The test is that the matching substring must either be at the beginning of the line, or w, -word-regexp Select only those lines containing matches that form whole words. v, -invert-match Invert the sense of matching, to select non-matching lines. i, -ignore-case Ignore case distinctions in both the PATTERN and the input files. The empty file contains zero patterns, and therefore matches nothing. f FILE, -file= FILE Obtain patterns from FILE, one per line. This can be used to specify multiple search patterns, or to protect a pattern beginning with a hyphen ( -). Matching Control -e PATTERN, -regexp= PATTERN Use PATTERN as the pattern. This is highly experimental and grep -P may warn of unimplemented features. P, -perl-regexp Interpret PATTERN as a Perl regular expression. G, -basic-regexp Interpret PATTERN as a basic regular expression (BRE, see below). F, -fixed-strings Interpret PATTERN as a list of fixed strings, separated by newlines, any of which is to be matched. Matcher Selection -E, -extended-regexp Interpret PATTERN as an extended regular expression (ERE, see below). This version number should be included in all bug reports (see below). V, -version Print the version number of grep to the standard output stream. Print a usage message briefly summarizing these command-line options and the bug-reporting address, then exit. Direct invocation as either egrep or fgrep is deprecated, but is provided to allow historical applications that rely on them to In addition, two variant programs egrep and fgrep are available. By default, grep prints the matching lines. These are just a few examples on how you can monitor and gather system and process statistics via top command.Grep searches the named input FILEs (or standard input if no files are named, or if a single hyphen-minus ( -) is given as file name)įor lines containing a match to the given PATTERN. $ for i in do sleep 2 & top -b -p 678 -n1 | tail -1 done > cron.txt We’ll use the same cron PID as shown in the above example. The output of the loop can also be redirected to a file. Using a for iteration loop, we can display a process statistics via its PID, each two seconds, as shown in the below example. In this example we’ll monitor the cron process via top command by taking three snapshots of the PID. To get the PID of a running process, issue pidof command against the name of the running process. To take a snapshot of a specific process in top utility, execute command with the PID (-p) flag. In order to display only the number of running tasks from the resulted file, use the grep filter, as shown in the below command example.