To perform a case insensitive (ignore case) search, use: grep -i 'pattern' filename To search for a whole word, not a part of a word, use: grep -w 'word' /path/to/file To search directories recursively, use the following: grep -r 'hello' /path/to/dir
To search for an exact pattern, use the following: grep -F "pattern" /path/to/file To search all files in the current directory, use the following: grep pattern * To search for a pattern within a file, use the following: grep "pattern" /path/to/file The general syntax of the grep command is: grep grep was initially developed for the Unix operating system but eventually made available for all Unix-like systems, such as Linux. When it finds a match in a line, grep copies the line to standard output or whatever output you select using options. For a pattern at the end then use “$”.Grep ( global regular expression printer) searches through a file for a specific pattern of characters. If looking for something at the starting, then use “^”. There are regular expressions which we need sometimes to use with the grep commands.
Using grep examples zip#
Zgrep is the command we use when we need to search for a pattern from zip file. This is the reason I always prefer to use egrep with the grep options we have discussed above ZGREP With grep command special characters like (, ), , \?, \+, \| which boosts the search pattern better. grep -c “create_clock” file1.sdc EGREPĮGREP stands for Extended Global Regular Expression Print. If you are looking for the pattern count in a file or files or files present in sub-directories, then use “-c” option. Sometimes we need to look into the files where search pattern is present then we use “-l” (small L). Many times, when we search for the string can be a sub-string of another string and will be printed while using the regular grep command, if one want to avoid the sub-string part then use “-w” option. If you are looking to search in all the files and directories present in the current directory, then use “*” at the place of file_name. grep -C 4 “data arrival time” timing.rpt #This command will print the line of 2 line above and after data arrival time. Similar to “-B” and “-A” options if one is looking to print before and after lines then use “-C ” option. grep -A 3 “data arrival time” timing.rpt #This command will give the line of 3 line above data arrival time. Similar to above if you want to print few numbers of lines after the search pattern then use “-A ”. grep -B 2 “data arrival time” timing.rpt #This command will give the line of 2 line above data arrival time. If you are looking for particular pattern in a report file, then you can use direct grep command but if 1 or 2 or few lines back we are looking to print then we use “-B ” option. If you are looking for some pattern but wants to exclude a string from that particular line, then use -v. wĪs we know grep command is case sensitive so when we search for particular string then it looks for same matching string, suppose we have upper and lower both cases present and need to grep out then use below command. If you are looking for the particular word to print rather than entire line, then use below command. One can go for cascaded grep command where first search string will be searched first and from them it will look for second search string.
If using grep command and looking for the search in all files and subdirectories present in current directory then use “-r” option along with grep, Where -r is recursive search method. “wc -l and -c” gives count of the pattern. If you are looking for the count of particular pattern, then use below two types of command. If there are directories present in the present working, then grep searches into these directories as well. Dot (.) represents the present working directory. If we are in particular directory and need to search from each file in this directory, then use below command. grep create_clock file1.sdc file2.sdc file3.sdc file4.sdc We can use multiple file at a time to search for the pattern. If I want to print all the lines which contains create_clock from file1.sdc then we use below example.
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