What does echo $? do?
58453
How do I look up exit codes for applications?
130753
Why does this echo call overwrite existing text?
59642
Strange echo, print behaviour in PHP?
12588
echo "#!" fails -- "event not found"
54322
What is the difference between the "...", '...', $'...', and $"..." quotes in the shell?
43522
What is the "?" symbol in URL used for in php?
38529
How do I get help for "echo" or other bash commands?
15213
How to echo an echo in php?
103049
What can I do if bash stops echoing?
36359
What does $# mean in shell?
58687
What is the difference between $(command) and `command` in shell programming?
125882
Could someone please explain this bash command?
61814
What is the "eval" command in bash?
101854
What is the difference between $@ and $* in shell scripts?
102224
Does variable=$(...) store the command or the result of the command in POSIX sh
105006
What is wrong with “echo $(stuff)” or “echo `stuff`”?
38430
In PHP, what does the ${$ } syntax do?