# ps(1)
```
ps [opt]
opt:
--no-header .... do not print column header
-o <OUT> ....... comma separated list of output columns
-p <PID> ....... only show pid
-C <name> ...... only show processes matching name
-T ............. list threads
--signames ..... use short signames instead bitmasks
```
> Set `PS_FORMAT` env variable to setup default output columns.
Frequently used output columns
```
pid process id
ppid parent process id
pgid process group id
tid thread id
comm name of process
cmd name of process + args (full)
etime elapsed time (since process started)
user user owning process
thcount thread count of process
nice nice value (-20 highest priority to 19 lowest)
pcpu cpu utilization (percent)
pmem physical resident set (rss) (percent)
rss physical memory (in kb)
vsz virtual memory (in kb)
sig mask of pending signals
sigcatch mask of caught signals
sigignore mask of ignored signals
sigmask mask of blocked signals
```
## Example: Use output for scripting
```sh
# Print the cpu affinity for each thread of process 31084.
for tid in $(ps -o tid --no-header -T -p 31084); do
taskset -c -p $tid;
done
```
## Example: Watch processes by name
```sh
watch -n1 ps -o pid,pcpu,pmem,rss,vsz,state,user,comm -C fish
```
## Example: Show signal information
```sh
# With signal masks.
ps -o pid,user,sig,sigcatch,sigignore,sigmask,comm -p 66570
# With signal names.
ps --signames -o pid,user,sig,sigcatch,sigignore,sigmask,comm -p 66570
```
