
bash - What are the special dollar sign shell variables ... - Stack ...
Sep 14, 2012 · In Bash, there appear to be several variables which hold special, consistently-meaning values. For instance, ./myprogram &; echo $! will return the PID of the process …
bash - Shell equality operators (=, ==, -eq) - Stack Overflow
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" …
bash - What is the purpose of "&&" in a shell command? - Stack …
Oct 27, 2021 · 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 …
shell - Bash regex =~ operator - Stack Overflow
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 …
linux - What does $@ mean in a shell script? - Stack Overflow
Apr 3, 2012 · (View Special parameters - Bash Manual) For instance, if you call ./someScript.sh foo bar then $@ will be equal to foo bar. If you do:./someScript.sh foo bar and then inside …
How do AND and OR operators work in Bash? - Stack Overflow
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 …
Meaning of $? (dollar question mark) in shell scripts
Aug 1, 2019 · In Bash, when you hit enter, a fork + exec + wait happens like above, and bash then sets $? to the exit status of the forked process. Note: for built-in commands like echo, a …
What's the difference between <<, <<< and < < in bash?
Sep 27, 2015 · In bash these are implemented via temp files, usually in the form /tmp/sh-thd.<random string>, while in dash they are implemented as anonymous pipes. This can be …
How to compare strings in Bash - Stack Overflow
Feb 10, 2010 · Bash always seemed backward with numeric evaluations using an operator consisting of a string (-eq) and string comparisons using a numeric operator "==" or "=" just …
bash - Precedence of the shell logical operators &&, || - Unix
This is not the case with Bash, however, in which both operators have the same precedence, which is why Bash parses your expression using the left-associativity rule. Thanks to Kevin's …