2>/dev/null do i=$(((i+1) % 4)) printf "." sleep1 done } cmd_with_process() { $1 & pid=$! process $pid & wait $pid if [ $? -eq 0 ]; then echogreen "[ok]" else echo_red "[fail]" fi } case $ in check_cmd) shift cm
在Bash脚本中,要删除尾随子串并且不区分大小写,可以使用字符串操作和正则表达式的结合。 以下是一个示例的Bash脚本代码: 代码语言:bash 复制 #!/bin/bashstring="Hello World"substring="world"# 将字符串转换为小写lowercase_string=${string,,}# 将子串转换为小写lowercase_substring=${substring,,}# 使用...
--password=PASS set both ftp and http password to PASS --ask-password prompt for passwords --use-askpass=COMMAND specify credential handler for requesting username and password. If no COMMAND is specified the WGET_ASKPASS or the SSH_ASKPASS environment variable is used. --no-iri turn off IRI...
if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then # We have color support; assume it's compliant with Ecma-48 # (ISO/IEC-6429). (Lack of such support is extremely rare, and such # a case would tend to support setf rather than setaf.) color_prompt=yes else color_...
# expand to default variableecho ${NULL-"Not null"} # Not nullecho ${NULL} ## set default variableecho ${NIL="Not nil"} # Not nilecho ${NIL} # Not nil 可以看出,前者只是当变量不存在时,展开成指定的值。而后者在变量不存在时,将变量的值设置为指定值。
The -p option changes the output format to that specified by POSIX. The TIMEFORMAT variable may be set to a format string that spec- ifies how the timing information should be displayed; see the description of TIMEFORMAT under Shell Variables below. Each command in a pipeline is executed ...
shell 在bash脚本中配置set -euo pipefail时，尝试使用命令输出设置变量时出错export是一个有退出代码的...
set variable-name value 除了普通赋值形式,readline变量可以赋予On或Off值(大小写字母均可)。在读取变量时,空串、NULL、on或1等价于On,off或0等其他情况等价于Off。readline支持的部分变量及其默认值简述如下:comment-begin(‘‘#’’) 当执行readline的insert-comment命令时,可以插入定义的字符串。这个命令捆绑到“...
# var: variable to set. # var2>var: Condition to test. # ?var2: If the test succeeds. # :var: If the test fails. ((var=var2>var?var2:var)) TRAPS 陷阱允许脚本在各种信号上执行代码。在pxltrm(用bash编写的像素艺术编辑器)中,陷阱用于在窗口大小调整时重绘用户界面。另一个用例是在脚本退...
if ! type -p convert &>/dev/null; then printf '%s\n' "error: convert is not installed, exiting..." exit 1 fi使用strftime获取当前日期Bash的printf有一个内置的获取日期的方法,可用来代替date命令。警告: 要求bash版本4+示例函数:date() { # 用法: date "format" # 通过"man strftime"看格式 ...