Re:Pure Bash Bible
by dyanaraps on Thursday September 19, 2019 @03:34AM
(#21014125)
Off the top of my head, a few notable things I've learned:
- Safely working with "string lists" (list="el el el el").
- Filtering out duplicate items.
- Reversing the list.
- etc.
- Using `case` to do sub-string matching (using globbing).
- Using `set -- el el el` to create an "array" (only one array at a time!).
- `read -r` is still powerful in POSIX `sh` for getting data out of files. `while read -r` even more so.
- POSIX `sh` has `set -e` and friends so you can exit on errors etc.
- Ternary operators still exist for arithmetic (`$(($# > 0 ? 1 : 0))`).
- Each POSIX `sh` shell has a set of quirks you need to account for. What works in one POSIX `sh` shell may not in another. (I found a set of differences between `ash`/`dash` in my testing).
POSIX `sh` is a very simple language compared to `bash` and all of its extensions so there won't be as many snippets but there's some gold to be found.
- Safely working with "string lists" (list="el el el el").
- Using `case` to do sub-string matching (using globbing).- Using `set -- el el el` to create an "array" (only one array at a time!).
- `read -r` is still powerful in POSIX `sh` for getting data out of files. `while read -r` even more so.
- POSIX `sh` has `set -e` and friends so you can exit on errors etc.
- Ternary operators still exist for arithmetic (`$(($# > 0 ? 1 : 0))`).
- Each POSIX `sh` shell has a set of quirks you need to account for. What works in one POSIX `sh` shell may not in another. (I found a set of differences between `ash`/`dash` in my testing).
POSIX `sh` is a very simple language compared to `bash` and all of its extensions so there won't be as many snippets but there's some gold to be found.