# PSRE README

Psre is short for **Process Snapshot Regex**. Essentially it is a simple
interface to quickly find PIDs of processes based on a regex match on the
`cmdline` in `/proc`. The normal operation is to run `ps` with any number of
flags, piped to any number of stream processors to extract matching process
IDs.

With `psre`, the command can be for example, `psre 'reg.*ex'`, to list all
processes with `reg` followed anywhere by `ex`. If the user wants to print a
list of the commands with the processes, the `-c,--cmdline` option can be
passed and the cmdline value will be printed next to the pid following a tab
character for easier splitting.

**Note** that when using `-c,--cmdline`, the original cmdline files in `/proc`
null-byte delimit the arguments of a command, leaving it only partially
printable. `psre` replaces those null bytes with the ascii space char (`0x20`
or `32 dec`) so the full cmdline is printable.


## Example Usage: Bulk killing stuck processes

Sometimes webkit spins up many sub processes which get stuck and only a `kill
-9` will shut them down. This can be very cumbersome to fix by hand as there
can be many stuck PIDs. To do this easily with `psre`, run the following:

```
kill -9 $(psre webkit --noself)
```

**Note** the `--noself` switch which causes `psre` to filter its own PID from
the list so it is not also killed or an error thrown when this command runs.