$ ls -l | > while read perms links owner group size month day time file > do > printf "%10d %s\n" "$size" "$file" > totalsize=$(( ${totalsize:=0} + ${size:-0} )) > done $ echo ${totalsize-unset} ## print "unset"
set -u选项会将bash shell未设置的变量视为错误并立即退出。使用未设置的变量是导致shell脚本误的常见原因之一，所以，对为设置变量，提示错误并退出很有必要。上面的脚本中，打印未初始化的变量导致结果打印了了我们不期望 的空行。如果我们使用-u选项（或者脚本中设置set -u）结果会立即抛出异常"a： unbound vari...
set +e 取消 #!/usr/bash set -e set +e var echo "hello world" 执行上面脚本,结果如下 test: line 5: var: command not found hello world 注意:管道命令有一个失败,脚本也不会停止 -o 参数 pipefail 可以与-e参数配合使用,管道命令只需一个不成功则脚本断开 如果设置,则管道的返回值是以非零状态...
更多关于set -euo pipefail的解释可以在这里找到:gnu.org/software/bash/manual/html_node/the-set-builtin.html set -euo pipefail; shopt -s failglob # safe mode @Tomhale,你能正确回答bashfaq 105(re:set -e角箱)中的每个练习吗?你确信你永远不会碰到ulm.de/~mascheck/variable/set-e中的任何可移...
If no COMMAND is specified the WGET_ASKPASS or the SSH_ASKPASS environment variable is used. --no-iri turn off IRI support --local-encoding=ENC use ENC as the local encoding for IRIs --remote-encoding=ENC use ENC as the default remote encoding --unlink remove file before clobber --keep...
set to a non-empty string (1)# $JAIL set to the empty string (2)# $JAIL can be unset (3)###echo "*** Current value of \$JAIL is '$JAIL' ($HINT) ***" ## Determine if a bash variable is empty or not ##if [ -z "${JAIL}" ]; then echo "JAIL is unset or set...
. ERROR: There was an error in main context, details to follow ERROR: Copy from mac-pro-1-1 had problems, will not continue If I fail, do I have to do this all over again? Using a checkpointSuppose that the remote copy is the most expensive operation of this whole script and that...
如果失败的命令是 shell,则 shell 不会退出 命令列表的一部分紧跟在 while 或 Until 关键字之后,部分 if 语句中测试的一部分,&& 或 || 的一部分列表,... 子shell 后跟“|| exit $?”显然算作命令列表;并且 bash -e 标志不适用于子 shell 内的任何命令。尝试一下: $ set -e $ ( echo before the ...
#!/bin/bash set -euo pipefail echo $a echo "bar" # output # --- # line 5: a: unbound variable set -x set -x 可以让Bash把每个命令在执行前先打印出来,你可以认为这就是Bash的Debug开关。它的好处当然显而易见,方便你快速找到有问题的脚本位置,但是也坏处也有吧,就是Bash的log会格外的乱。另...
check-scripts:# Fail if any of these files have warningsshellcheck myscripts/*.sh or in a Travis CI.travis.ymlfile: script:# Fail if any of these files have warnings-shellcheckmyscripts/*.sh Services and platforms that have ShellCheck pre-installed and ready to use: ...