Adding to tripleee‘s answer: It is important to remember that the section of the script formatted as a here-document for another shell is executed in a different shell with its own environment (and maybe even on a different machine). If that block of your script contains parameter expansion, command substitution, and/or arithmetic expansion, then you … Read more
echo -e $lines | while read line … done The while loop is executed in a subshell. So any changes you do to the variable will not be available once the subshell exits. Instead you can use a here string to re-write the while loop to be in the main shell process; only echo -e … Read more
You cannot have spaces around the = sign. When you write: STR = “foo” bash tries to run a command named STR with 2 arguments (the strings = and foo) When you write: STR =foo bash tries to run a command named STR with 1 argument (the string =foo) When you write: STR= foo bash … Read more
What is sh? sh (or the Shell Command Language) is a programming language described by the POSIX standard. It has many implementations (ksh88, Dash, …). Bash can also be considered an implementation of sh (see below). Because sh is a specification, not an implementation, /bin/sh is a symlink (or a hard link) to an actual … Read more
Yes. Bash scripts are sensitive to line-endings, both in the script itself and in data it processes. They should have Unix-style line-endings, i.e., each line is terminated with a Line Feed character (decimal 10, hex 0A in ASCII). DOS/Windows line endings in the script With Windows or DOS-style line endings , each line is terminated … Read more
You can use Marcus’s answer (* wildcards) outside a case statement, too, if you use double brackets: string=’My long string’ if [[ $string == *”My long”* ]]; then echo “It’s there!” fi Note that spaces in the needle string need to be placed between double quotes, and the * wildcards should be outside. Also note … Read more