shell

问题 This outputs before\n : #!/usr/bin/env bash set -e echo before ((0)) echo after Removing set -e or changing ((0)) to ((1)) makes the program output before\nafter\n as expected. Why does ((0)) trigger the set -e exit condition? 回答1: This will explain: ((0)) echo $? 1 ((1)) echo $? 0 So it is due to non-zero return status of arithmetic expression evaluation in (( and )) your script is exiting when set -e is being used. As help set says this: -e Exit immediately if a command exits with a non

问题 The following is the content stored in my file This is my Input So, using wc -c command we can get the number of characters stored in the file. My expected output for above file that edited by using VIM in Ubuntu is 16. But, wc -c command returns 17 . Why is the output like this? There isn't even a carriage return at end of line. So, what is the 17th character? 回答1: of course you had enter. maybe you cant see it. consider these two examples: echo -n "This is my Input" | wc -c 16 because -n is

问题 I did a=1234 let "a=a+1" on command line and it's fine. But when I do the same in a shell script. It prints out an error that "let: not found". Here is the script file. #!/bin/sh a=1234; let "a=a+1"; echo "$a"; Thanks, 回答1: The problem is likely that /bin/sh is not the same as, or does not behave the same as, your normal shell. For example, when bash is invoked as /bin/sh , it provides a subset of its normal features. So, you may need to change your shebang line to use a different shell: #!

问题 I try so send some files toward multiple servers using scp in bash script. But I encountering problem. here is the shell script I wrote. #!/bin/sh IP_LIST=('127.0.0.x' '127.0.0.y' '127.0.0.z') for ip_addr in "${IP_LIST[@]}" do echo "$ip_addr" expect << 'EOS' set timeout 10 spawn scp -p /home/foo/bar/baz.txt user@"$ip_addr":/home/destdir expect "*password*" send "pasword\r" expect eos exit 0 EOS done I assume each element in ip_addr is assigned to the variable ip_addr , but in expect session,

问题 I try so send some files toward multiple servers using scp in bash script. But I encountering problem. here is the shell script I wrote. #!/bin/sh IP_LIST=('127.0.0.x' '127.0.0.y' '127.0.0.z') for ip_addr in "${IP_LIST[@]}" do echo "$ip_addr" expect << 'EOS' set timeout 10 spawn scp -p /home/foo/bar/baz.txt user@"$ip_addr":/home/destdir expect "*password*" send "pasword\r" expect eos exit 0 EOS done I assume each element in ip_addr is assigned to the variable ip_addr , but in expect session,

问题 Is it possible to use xdotool to enter a web console command like this command: $("#var2").css("move", - 44 + "deg") 回答1: Yes is possible, you can use web console or address bar. with this step: Focus on Browser press F12 Type code this example xdotool script using web console: search --sync --onlyvisible --name "chrome" windowactivate --sync keydown F12 sleep 1 type --clearmodifiers --delay 10 --args 1 "document.getElementsByTagName('body')[0].style.backgroundColor = 'green'" sleep 1 key

问题 I have a python program that needs to run a bash command on a server. The program works when I run a bash command in my local directory like this: import subprocess from subprocess import call call(['bash', 'Script_Test.sh']) However, after SSH'ing to a server and running a similar line of code below with a path on the server to a bash script, I get the error "No such file or directory" call['bash', path] This doesn't make sense for a number of reasons. I triple checked that the path is

问题 What terminal command can I use to terminate the cursor/mouse process on a MacOSX? I'm changing the size of the mouse using another command in the terminal and now I need to restart the process that displays the cursor. I have searched for hours for a similar topic, but couldn't find one. Does anybody know how to achieve this? 回答1: If by "changing the size of the mouse using another command in the terminal", you mean that you set the System Preferences value (i.e. using 'defaults' command),

问题 All we know that cron ignores variables defined in “.bashrc” and “.bash_profile”, so we have to define it inside cron. I constantly do the same what was written inside the similar question https://unix.stackexchange.com/questions/67940/cron-ignores-variables-defined-in-bashrc-and-bash-profile but still global variables inside .bashrc still not working. I found way to execute it - by defining sh script with "set +a" bashrc script. But "source" still doesn't work. SHELL=/bin/bash BASH_ENV=/root

问题 Creating a search and replace function for my application, I am running a test scenario with 3 files, array tscript test I am trying to escape double quotation marks but it wont work script file contains variableName=$1 sed "s#data\-field\=\"${variableName}\.name\"#data\-field\=${variableName}\.name data\-type\=dropdown data\-dropdown\-type\=${variableName}#g" test test file contains data-field=“fee_category.name” data-field=“tax_type.name” array file contains fee_category tax_type There is