[FORGED] file.exists() on device files
Thank you for the insights, Rolf and Henrik.
To give another example, this time in non-interactive mode,
Rscript -e "file.exists(commandArgs(TRUE))" <(echo "Hi")
[1] TRUE
versus
Rscript -e "normalizePath(commandArgs(TRUE))" <(echo "Hi")
[1] "/dev/fd/63"
Warning message:
In normalizePath(commandArgs(TRUE)) :
path[1]="/dev/fd/63": No such file or directory
It almost seems like file.exists and normalizePath use separate criteria
for determining existence?
Regards
Ben
On 01/12/2017 01:42 AM, Rolf Turner wrote:
On 12/01/17 16:33, Henrik Bengtsson wrote: <SNIP>
FYI, the /proc is there because Unix has something called the "proc filesystem (procfs; https://en.wikipedia.org/wiki/Procfs) is a special filesystem in Unix-like operating systems that presents information about processes and other system information in a hierarchical file-like structure". For instance, you can query the uptime of the machine by reading from /proc/uptime: $ cat /proc/uptime 332826.96 661438.10 $ cat /proc/uptime 332871.40 661568.50 You can get all IDs (PIDs) of all processes currently running: $ ls /proc/ | grep -E '^[0-9]+$' and for each process you there are multiple attributes mapped as files, e.g. if I start R as: $ R --args -e "message('hello there')" then I can query that process as: $ pid=$(pidof R) $ echo $pid 26323 $ cat /proc/26323/cmdline /usr/lib/R/bin/exec/R--args-emessage('hello there') Unix is neat
Indeed. Couldn't agree more. Thanks for the insight. <SNIP> cheers, Rolf