Other Comparison Operators Note that integer and string comparison use a different set of operators. ... String=' ' # Zero-length ("null") string variable. if [ -z "$String" ] then echo "\$String is null. ... bin/bash # str-test.sh: Testing null strings and unquoted strings, #
Linux shell編程——if條件判斷 - wokaotesting - 博客頻道 - CSDN.NET [macg@mac-home ~]$ vi test.sh: echo "input the num:" read num echo "input is $num" if [ -z "$JHHOME" -a -d $HOME/$num ] 如果變數$JHHOME為空，且$HOME/$num目錄存在 then JHHOME=$HOME/$num 則賦值 fi echo "JHHOME is ...
If / Else Statements (Shell/bash Scripting) | Sany's Linux and Open Source Blog Shell scripts use fairly standard syntax for if statements. The conditional statement is executed using either the test command or the [ command ]. In its most basic form an if statement is: #!/bin/bash if [ "$1" -eq "abc" ] then echo "in if block" fi (No
linux shell中 if else以及大於、小於、等於邏輯表達式介紹_linux shell_腳本之家 在linux shell編程中，大多數情況下，可以使用測試命令來對條件進行測試，這裡簡單的介紹下，方便需要的朋友 ... 比如比較字元串、判斷文件是否存在及是否可讀等，通常用"[]"來表示條件測試。註意：這裡的空格很重要。
shell编程——if语句if -z -n -f -eq -ne -lt - 博客园 2012年7月5日 ... if command then if 函数 then, 命令执行成功，等于返回0 （比如grep ,找到匹配） 执行 失败，返回非0 （grep,没找到匹配）. if [ expression_r_r_r ]
shell编程——if语句_macg_新浪博客 2009年8月6日 ... if command then if 函数 then, 命令执行成功，等于返回0 （比如grep ,找到匹配 ... vi testsh.sh #!/bin/sh cat 111-tmp.txt | grep ting1 if [ $? -eq 0 ] then
What does if [ $? -eq 0 ] mean for shell scripts? - Stack Overflow It's checking the return value ($?) of grep. In this case it's comparing it to 0 (success). Usually when you see something like this (checking the return value of grep) it's checking to see whether the particular string was detected. Although the redirect
Shell if else語句_Shell中文網 - 西安電子科技大學電子工程學院 if 語句通過關係運算符判斷表達式的真假來決定執行哪個分支。Shell 有三種 if ... else 語句： if ... fi 語句； if ... else ... fi 語句； if ... elif ... else ... fi 語句。 1) if ... else 語句 if ... else 語句的語法： if [ expression ] then Statement(s) to be executed if expression is ...
Working with IF, ELSE and ELSE IF in Bash Shell Scripting - TecAdmin.net How to use If, ELSE, ELIF conditional statements in bash shell scripting (bash programming), with useful examples. ... IF, ELSE or ELIF (known as else if in other programming) are conditional statements which are used for execution of different-2 programm
shell - Bash: double equals vs -eq - Unix & Linux Stack Exchange 5 Jul 2011 ... I am doing integer comparison in bash (trying to see if the user is running as root) , and I found two ...
