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How do you check if a file contains a string in shell script?
- Just use grep with flags ‘F’ (fixed string), ‘x’ (exact match) and ‘q’
- (quiet output) in order to check if a word string is in a file.
- if grep -Fxq “string” file. txt; then #do some code…#; fi.
How do you check if a line contains a string in bash?
The easiest approach is to surround the substring with asterisk wildcard symbols (asterisk) * and compare it with the string. Wildcard is a symbol used to represent zero, one or more characters. If the test returns true , the substring is contained in the string.
How do I search for a string in a file in Linux?
To search recursively, use the -r option with grep . As you can see, grep searched multiple directories and indicates where it found the string. You could also specify a directory in your command, but omitting it (as we did in this example) will instruct grep to search every directory in the current path.
How to check if a file contains a specific line?
I need to check if a file contains a specific line. This file is written continuously by someone, so I put the check inside a while loop. The file contains text and multiple lines. if $FILE contains the file name and $STRING contains the string to be searched, then you can display if the file matches using the following command:
How to check if a file contains a specific string using Bash?
You don’t need [ [ ]] here. Just run the command directly. Add -q option when you don’t need the string displayed when it was found. The grep command returns 0 or 1 in the exit code depending on the result of search. 0 if something was found; 1 otherwise.
How to find lines containing a string in Linux stack?
Each line which matches the pattern will be output. If you want to search for fixed strings only, use grep -F ‘pattern’ file. Besides grep, you can also use other utilities such as awk or sed
How to get all lines containing a string in a huge text file?
In Powershell, how to read and get as fast as possible the last line (or all the lines) which contains a specific string in a huge text file (about 200000 lines / 30 MBytes) ? I’m using : But it’s very very long (about 16-18 seconds).