Saving and restoring standard file descriptors of shell scripts

[Angel Tsankov]

How can a shell script save and restore its standard file descriptors (stdin, stdout and stderr)?

[kermit]

Post by Angel Tsankov
How can a shell script save and restore its standard file descriptors
(stdin, stdout and stderr)?

one common trick is

# move FD 1 to FD 20
exec 20>&1 1>&/some/other/file
...

# move FD 1 back to original
exec 1>&20

this assumes that shell supports multidigit FD number (some older shells do
not) and FD 20 is not used (e.g. it may be inherited and contain SSH agent
connection ...)