2.0 KiB
====== Grouping commands ======
===== Synopsis =====
{ ; }
{
}
===== Description =====
The list '''' is simply executed in the current shell environment. The list must be terminated with a newline or semicolon. For parsing reasons, the curly braces must be separated from '''' by a semicolon and blanks if they're in the same line! ((Actually any properly terminated compound command will work without extra separator (also in some other shells), example: ''{ while sleep 1; do echo ZzZzzZ; done }'' is valid. But this is not documented, infact the documentation explicitly says that a semicolon or a newline must separate the enclosed list. -- thanks ''geirha'' at Freenode))((The main reason is the fact that in shell grammar, the curly braces are not control operators but reserved words -- TheBonsai))
This is known as a group command. The return status is the exit status (exit code) of the list.
The input and output filedescriptors are cumulative:
{
echo "PASSWD follows"
cat /etc/passwd
echo
echo "GROUPS follows"
cat /etc/group
} >output.txt
This compound command also usually is the body of a function definition, though not the only compound command that's valid there:
print_help() {
echo "Options:"
echo "-h This help text"
echo "-f FILE Use config file FILE"
echo "-u USER Run as user USER"
}
===== Examples ===== ==== A Try-Catch block ====
try_catch() {
{ # Try-block:
eval "$@"
} ||
{ # Catch-block:
echo "An error occurred"
return -1
}
}
===== Portability considerations =====
===== See also =====