Apparemment trivial, ce programme est extrmement puissant. Cela signifie que vous pouvez utiliser grep pour voir si l’entre qu’il reoit correspond un modle spcifi. If the variables contain spaces or other unusual characters it will probably cause the script to fail. L’accronyme grep signifie global regular expression print (rechercher globalement les correspondances avec l’expression rgulire). The reason for this is explained by 8jean in another answer. For anything touching regular expression patterns you should check the excellent BBEdits menu Help > BBEdit Help > Grep Reference. Java 4 and 5 have bugs that cause lookbehind with alternation or variable quantifiers to fail when it should succeed in some situations. Take particular note of the double-quotes used to wrap the variables. # Symbolic link specific commands go here. So symbolic links may have to be treated differently, if subsequent commands expect directories: if then The \ (single backslash) character tells the grep command to treat the following character (in this example the ) as a. The \\ (double backslash) characters are necessary in order to force the shell to pass a \ (single backslash, dollar sign) to the grep command. When -regex is used with -all, this behavior changes. Will produce the error message: rmdir: failed to remove `symlink': Not a directory To search for a (dollar sign) in the file named test2, enter: grep \\ test2. If it did not match, the variable will be set to nothing (like set var ). running this: ln -s "$ACTUAL_DIR" "$SYMLINK" I was able to use echo in the terminal to pipe a string into grep, like this: echo 'filename.txt.123' egrep -o '\. However, as Jon Ericson points out, subsequent commands may not work as intended if you do not take into account that a symbolic link to a directory will also pass this check.Į.g. I'm writing a bash script and I need to check if a file name has a number at the end (after a period) and if so get it, but I can't figure out how to use regex on a variable or string. ![]() # Control will enter here if $DIRECTORY doesn't exist. Or to check if a directory doesn't exist: if then # Control will enter here if $DIRECTORY exists. To check if a directory exists in a shell script, you can use the following: if then
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