Bash

Bash in Engineering

• (Chinese) bash的常用功能和技巧 - 百度运维

Problems

• unexpected operator - ./test.sh: 4: [: Linux: unexpected operator
  • File Content:

    !/bin/sh

    if [ "$(expr substr $(uname -s) 1 5)" == "Linux" ]; then echo "Script running under GNU/Linux"

  • System: GNU/Linux (Ubuntu 12.04)
  • Solution: Ubuntu replace bash with dash since Ubuntu 6, you can see with ls -l /bin you will see sh -> dash. Use #!/bin/bash instead of #!/bin/sh, or use = instead of == when comparing two strings.