shell

问题 This question already has answers here : How do I iterate over a range of numbers defined by variables in Bash? (20 answers) Closed 5 years ago . If I do this, I get the result as expected. for i in {125..129}; do echo $i; done 125 126 127 128 129 But when I do this? I get something weired. for i in {$((1+(25-1)*500))..$((25*500))}; do echo $i; done {12001..12500} I wish to pass a variable inside the loop variables like $((1+($j-1)*500)) 回答1: Bash's brace expansion has limitations. What you

问题 In Git SCM I'm using the following command to check whether a specific revision is present on some remote: git fetch <remote> <revision> -q --dry-run If the exit code of the command is zero that means the revision is present on the remote. For Mercurial I tried the following command: hg pull <remote> -r <revision> -q It works but the problem is that it actually pulls the revision if present on the remote, but not locally. Is there an equivalent of the --dry-run option for Git, or some other

问题 This question already has answers here : How to cat <<EOF >> a file containing code? (4 answers) Closed 2 years ago . I'm in need of some explanation of the following code, because they are the same concepts but not working the same. So, I'm trying to do the following: #!/bin/sh ssh -T username@host << EOF relative="$HOME/Documents" command=$(find \$relative -name GitHub) command2=$(echo \$relative) echo "HERE: \$command" echo "HERE: \$command2" EOF Here is the output I get: find: ‘$relative’

问题 What does sleep 0 do in a shell script? I read the man page for sleep and it says "delay for a specified amount of time" And the argument NUMBER specifies this time in SECONDS (by default). But I see ansible using sh -c 'echo ~ec2-user && sleep 0' to start with each task. Also, it uses this at the end of each remote command it is firing. I didn't find any special case mention of sleep 0 on the man page and based on the functionality of the sleep command it doesn't make any sense to have sleep

问题 I'm trying to match hostname with regex. For some reason the following code fails. #!/bin/bash CONFIGURATION=m1si-ngxi-ddb01 #check configuration format TMP_CONFIGURATION=",${CONFIGURATION}" re=',[a-zA-Z0-9\-_\.]+' if ! [[ $TMP_CONFIGURATION =~ $re ]] then echo "configuration parttern mismatch." exit 1 fi Testing: [oracle@m1s-nyyy-db01 nir]$ vi a.sh [oracle@m1s-nyyy-db01 nir]$ 回答1: The pattern you have is failing due to "escaped" chars and the fact that - is not at the end/start of the

问题 I have a Bash script which generates, stores and modifies values in an array. These values are later used as arguments for a command. For a MCVE I thought of an arbitrary command bash -c 'echo 0="$0" ; echo 1="$1"' which explains my problem. I will call my command with two arguments -option1=withoutspace and -option2="with space" . So it would look like this > bash -c 'echo 0="$0" ; echo 1="$1"' -option1=withoutspace -option2="with space" if the call to the command would be typed directly

问题 How can I read a JSON variable in shell script ( to be noted "JSON variable " and not JSON File)? I have tried something like, temp={\"name\":\"Sipdy\",\"time\":\"17:09 1985\",\"place\":\"CA\"} jq '.time' $temp and also tried temp={"name":"Sipdy","time":"17:09 1985","place":"CA"} jq '.time' $temp but both the above commands expect a JSON file name in place of "$temp". 回答1: You need to provide the JSON text as jq's standard input: $ temp='{"name":"Sipdy","time":"17:09 1985","place":"CA"}' $

问题 This question already has answers here : Test whether a glob has any matches in bash (20 answers) Closed 6 months ago . I want to check if only one instance of a file exists before going on to process that file. I can check how many instances exist using this command: ls -l $INPUT_DIR/${INPUT_FILE_PREFIX}cons*.csv.gz | wc -l; However, when I go to use this within an if statement, I am warned that the ls: command not found . if [ls -l $INPUT_DIR/${INPUT_FILE_PREFIX}cons*.csv.gz | wc -l = '1']

问题 This question already has answers here : Test whether a glob has any matches in bash (20 answers) Closed 6 months ago . I want to check if only one instance of a file exists before going on to process that file. I can check how many instances exist using this command: ls -l $INPUT_DIR/${INPUT_FILE_PREFIX}cons*.csv.gz | wc -l; However, when I go to use this within an if statement, I am warned that the ls: command not found . if [ls -l $INPUT_DIR/${INPUT_FILE_PREFIX}cons*.csv.gz | wc -l = '1']

问题 This question already has answers here : Test whether a glob has any matches in bash (20 answers) Closed 6 months ago . I want to check if only one instance of a file exists before going on to process that file. I can check how many instances exist using this command: ls -l $INPUT_DIR/${INPUT_FILE_PREFIX}cons*.csv.gz | wc -l; However, when I go to use this within an if statement, I am warned that the ls: command not found . if [ls -l $INPUT_DIR/${INPUT_FILE_PREFIX}cons*.csv.gz | wc -l = '1']