Ah yes, I suspected this was from set but wanted to see it in the manual. I was wondering why I didn't see it in man bash, it's because I went straight to the options listed and missed the paragraph that said "All of the single-character shell options documented in the description of the set builtin command, including -o, can be used as options when the shell is invoked".

2012年6月3日 · Also be aware that commands called from bash -c will be forced to singlethreading. eg: "bash -c 'ffmpeg -threads 4 -i input.mov output.mp4'" will call ffmpeg but it can only use one core even though you specified the "threads" parameter –

2013年10月18日 · The [[ ]] is treated specially by bash; consider that an augmented version of [ ] construct: [ ] is actually a shell built-in command, which, can actually be implemented as an external command. Look at your /usr/bin, there is most likely a program called "[" there! Strictly speaking, [ ] is not part of bash syntax.

2016年5月14日 · -s makes bash read commands (the "install.sh" code as downloaded by "curl") from stdin, and accept positional parameters nonetheless.--lets bash treat everything which follows as positional parameters instead of options. bash will set the variables $1 and $2 of the "install.sh" code to -P and to chefdk, respectively.

2012年4月18日 · $ man bash -e file True if file exists. -f file True if file exists and is a regular file. A regular file is something that isn't a directory, symlink, socket, device, etc.

The double bracket [[ exp ]] is a bash builtin. In bash -a and -e are the same, probably for some backwards compatibility. The single bracket [ exp ] is an alias for the external command "test". In "test", -a is a logical AND.

In bash, && and || have equal precendence and associate to the left. See Section 3.2.3 in the manual for details. So, your example is parsed as $ (echo this || echo that) && echo other And thus only the left-hand side of the or runs, since that succeeds the right-hand side doesn't need to …

2021年10月27日 · As far as I know, using & after the command is for running it in the background. Example of & usage: tar -czf file.tar.gz dirname & But how about &&? (example)

2013年7月17日 · If you use man bash instead of info bash, search for ^ *test (the word test at the beginning of a line, following some number of spaces). Following the reference to "Bash Conditional Expressions" will lead you to the description of -ne , which is the numeric inequality operator ("ne" stands for "not equal).

If not quoted, it is a pattern match! (From the Bash man page: "Any part of the pattern may be quoted to force it to be matched as a string."). Here in Bash, the two statements yielding "yes" are pattern matching, other three are string equality: