mirror of
https://github.com/fish-shell/fish-shell.git
synced 2024-11-30 06:03:49 +08:00
42 lines
1.5 KiB
Plaintext
42 lines
1.5 KiB
Plaintext
\section if if - conditionally execute a command
|
|
|
|
\subsection if-synopsis Synopsis
|
|
\fish{synopsis}
|
|
if CONDITION; COMMANDS_TRUE...;
|
|
[else if CONDITION2; COMMANDS_TRUE2...;]
|
|
[else; COMMANDS_FALSE...;]
|
|
end
|
|
\endfish
|
|
|
|
\subsection if-description Description
|
|
|
|
`if` will execute the command `CONDITION`. If the condition's exit status is 0, the commands `COMMANDS_TRUE` will execute. If the exit status is not 0 and `else` is given, `COMMANDS_FALSE` will be executed.
|
|
|
|
In order to use the exit status of multiple commands as the condition of an if block, use <a href="#begin">`begin; ...; end`</a> and the short circuit commands <a href="commands.html#and">`and`</a> and <a href="commands.html#or">`or`</a>.
|
|
|
|
The exit status of the last foreground command to exit can always be accessed using the <a href="index.html#variables-status">$status</a> variable.
|
|
|
|
|
|
\subsection if-example Example
|
|
|
|
The following code will print `foo.txt exists` if the file foo.txt exists and is a regular file, otherwise it will print `bar.txt exists` if the file bar.txt exists and is a regular file, otherwise it will print `foo.txt and bar.txt do not exist`.
|
|
|
|
\fish
|
|
if test -f foo.txt
|
|
echo foo.txt exists
|
|
else if test -f bar.txt
|
|
echo bar.txt exists
|
|
else
|
|
echo foo.txt and bar.txt do not exist
|
|
end
|
|
\endfish
|
|
|
|
The following code will print "foo.txt exists and is readable" if foo.txt is a regular file and readable
|
|
\fish
|
|
if begin test -f foo.txt
|
|
and test -r foo.txt
|
|
end
|
|
echo "foo.txt exists and is readable"
|
|
end
|
|
\endfish
|