5 ms·
Most of the mistakes are not exclusive/related to grep, they are actually shell mistakes.
by gnagatomo 6y ago
Most of the mistakes are not exclusive/related to grep, they are actually shell mistakes.
- Jenz 6y agoAnd simply regex mistakes.
- mturmon 6y agoThis is true, and I agree. But this kind of "language-within-language" problem (regex within sh) comes up a lot when formulating grep and sed command lines. Come to think of it, I think this is the most frequently-encountered class of "this line didn't do what I thought it would" type errors that I get as a near-daily user of (ba)sh for a few decades now. Question for the group: When you encounter this kind of issue, e.g. the shell is stealing a single or double quote meant to be in the regex, do you diagnose the problem w/r/t the shell precedence rules for quotes and backslashes, or do you just blindly put the opposite type of quote around the whole thing and re-run? Because probably half the time I use a basic blind strategy, and that's not usually how I approach programming errors!
- asicsp 6y agoagree, and the author continues to use double quotes around search pattern despite showing an example where single quote was needed! As a good practice, I always try to single quote the expression, even if it is not needed. Use double quote only when needed and even then, use it only for the portion required, not for the entire expression. https://mywiki.wooledge.org/Quotes https://mywiki.wooledge.org/Quotes is a must read.