I'm trying to understand some sequence of bash scripts, and on one of the steps there is a condition:
if [ "x/usr/bin" != "x" ]; then <do some actions>What do the following mean?
xinx/usr/binxin the right hand side of the testing equation?
1 Answer
It's a well known bashism.
If a variable (say $foo in this example) might be empty or might hold a value,
If foo="", then
if [ "$foo" = "bar" ]expands to
if [ = "bar" ]a syntax error :-(
If one uses
if [ "x$foo" = "xbar" ] it expands to
if [ "x" = "xbar" ]No syntax error.
There are better ways to check for empty variables, like
if [[ -n "$foo" ]]
