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diff --git a/src/content/tils/2020/11/12/useful-bashvars.adoc b/src/content/tils/2020/11/12/useful-bashvars.adoc deleted file mode 100644 index fb148fb..0000000 --- a/src/content/tils/2020/11/12/useful-bashvars.adoc +++ /dev/null @@ -1,61 +0,0 @@ -= Useful Bash variables -:categories: shell - -:bash: https://www.gnu.org/software/bash/ -:bash-bang-bang: https://www.gnu.org/software/bash/manual/bash.html#Event-Designators -:bash-dollar-underscore: https://www.gnu.org/software/bash/manual/bash.html#Special-Parameters - -{bash}[GNU Bash] has a few two letter variables that may be useful when typing -on the terminal. - -== `!!`: the text of the last command - -The {bash-bang-bang}[`!!` variable] refers to the previous command, and I find -useful when following chains for symlinks: - -[source,sh] ----- -$ which git -/run/current-system/sw/bin/git -$ readlink $(!!) -readlink $(which git) -/nix/store/5bgr1xpm4m0r72h9049jbbhagxdyrnyb-git-2.28.0/bin/git ----- - -It is also useful when you forget to prefix `sudo` to a command that requires -it: - -[source,sh] ----- -$ requires-sudo.sh -requires-sudo.sh: Permission denied -$ sudo !! -sudo ./requires-sudo.sh -# all good ----- - -Bash prints the command expansion before executing it, so it is better for you -to follow along what it is doing. - -== `$_`: most recent parameter - -The {bash-dollar-underscore}[`$_` variable] will give you the most recent -parameter you provided to a previous argument, which can save you typing -sometimes: - -[source,sh] ----- -# instead of... -$ mkdir -p a/b/c/d/ -$ cd a/b/c/d/ - -# ...you can: -$ mkdir -p a/b/c/d/ -$ cd $_ ----- - -== Conclusion - -I wouldn't use those in a script, as it would make the script terser to read, I -find those useful shortcut that are handy when writing at the interactive -terminal. |