$ grep -i 'it' recording_commands | wc -lĪnd here’s a little surprise. In the examples below, the word “it” is found 10 times in the first case and 11 times when the -i option is used. To find strings in text files regardless of whether the letters are in uppercase or lowercase, use the grep command’s -i (ignore case) option. The command below does not find the string. Note that the grep -e command will allow you to search for strings that begin with a hyphen. $ grep -w 'fly|sessio' recording_commands In other words, type "script" and each command that Their history command numbers during a single login session. When you first open a session on the command line, the oldest commands in $ grep -w 'fly|session' recording_commands In the examples below, the line containing the word “session” is only included when the full word is used in the command. The command below fails to find the word “xray” because the “y” is omitted and the -w option is used. If you only want to find exact matches for your strings, use a command like the one below that will only display strings when they are included in the file as full words – not substrings. $ grep -e ^xr -e tape -e hope -e boat 4letters In this case, each string is included following its own -e. The same search can be performed using grep‘s -e option. You can also use regular expressions like ^xr in commands to look for strings that begin with particular letters. This form of grep command is not limited to two strings. The “|” characters separate each word that you want to find. You can also use a command like the one below to find multiple strings. Another option is to list each string separately following the -e option. The -E option allows “extended regular expressions” to provide this function. The command will display any lines in the file that contain the word “xray”, the word “tape” or both. In the command below, the ‘|’ character serves as an “or” function. There are a number of ways to search for a group of strings in a single command. The wording suggests there was more to the story than anyone wanted to admit. This “find string in file” command will show all the lines in the file that contain the string, even when that string is only part of a longer one. The simplest grep command looks like the one shown below. This post shows how to use grep in all these ways. It can also ignore case when needed, and it can count the lines in the resulting output for you. It can be used to search through these files for multiple strings or regular expressions at the same time. The output matches in both cases the output from running grep -c with each pattern individually.The grep command makes it easy to find strings in text files on Linux systems, but that’s just a start. Output with pat='^a a$ alfa beta gamma': beta 2 Output with pat='alfa beta gamma': alfa 1 Note if your pattern contains space, you need to use a different delimiter between the patterns in pat and to update the split command accordingly. The c?c:0 bit uses the ternary operator to print 0 when c is zero. Pat is split into the p array, which is then used to search for matches on each line ( $0 ~ p). Please tell me if there still are any open issues. Just give the search strings directly to the scriptįixed version with regex support (see comment below). Low end version with restrictions outlined in comments below: awk 'įor (i in a) print sprintf("%s %d", a, A]) But it's easy to add some features if so desired. And works for plain words only - not regexps. This solution may not work well for large files (is not optimized). I don't think grep is capable of what you want to do.
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