$ unset x $ showvar $x is not set $ x=3 $ showvar $x is not set $ export x $ showvar $x = 3 $ x= ## in bash, reassignment doesn't remove a variable from the environment $ showvar $x is set but empty 注意 showvar不是一个 bash 命令,而是一个如清单 5-1 所示的脚本,...
-k file 若文件存在且设置了"sticky"位的值 -p file 若文件存在且为一已命名管道,则为真 -r file 若文件存在且可读,则为真 -s file 若文件存在且其大小大于零,则为真 -u file 若文件存在且设置了SUID位,则为真 -w file 若文件存在且可写,则为真 -x file 若文件存在且可执行,则为真 -o file ...
:p Examine the previous file in the command line list. If a number N is specified, the N-th previous file is examined. :x Examine the first file in the command line list. If a number N is specified, the N-th file in the list is examined. :d Remove the current file from the li...
touch -- 'file with spaces' '-a' '-l' 'filename' # and some files: 即使使用奇数命名文件,命令echo ./*/仍然可靠: 12 ./--/ ./-/ ./*/ ./cs/ ./dir with spaces/ ./draft/ ./files/ ./-h/ ./masters/ ./-n/ ./static/ ./-v var/ 但是文件名中的空格会让阅读有点混乱。 如...
openssl: parse available options from $command -help (9e03fc5) openssl: complete -writerand with filenames (548feef) totem: reuse kaffeine completions (#372) (e4d5eba) test/cd: remove unused import (9a9f09f) test/totem: add basic test case (9c33f68) extra/make-changelog: run throu...
Bash reads and executes commands from this file, then exits. Bash's exit status is the exit status of the last command executed in the script. If no commands are executed, the exit status is 0. An attempt is first made to open the file in the current directory, and, if no file is...
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checks/check_sqlfluff.sh - recursively iterates all SQL code files found in the given or current directory and runs SQLFluff linter against them, inferring the different SQL dialects from each path/filename/extension AWS - Amazon Web Services aws/ directory: AWS scripts - aws_*.sh: aws_pr...
empty lines from files. By harnessing the power of regular expressions, we were able to identify and remove empty lines, as well as lines containing only whitespace characters. That can be pretty useful for a variety of scenarios, such as data preprocessing, text file cleanup, and much more....
# Creating an array with a string that contains spaces arr=("Hello World") # Printing the array echo ${arr[@]} # Output: # 'Hello World' In this example, even though the string “Hello World” contains a space, it’s treated as a single element in the array because we’ve used ...