ABOUT eval
eval is a builtin command of the Bash shell. It concatenates its arguments into a single string, joining the arguments with spaces, then executes that string as a bash command. It's similar to running bash -c "string", but eval executes the command in the current shell environment rather than creating a child shell process.
TYPICAL SHELL SESSION RELATED
[bash]
$eval ip address
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000
link/ether 70:5a:0f:b9:d8:5c brd ff:ff:ff:ff:ff:ff
3: wlp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 68:14:01:07:36:1f brd ff:ff:ff:ff:ff:ff
inet 192.168.1.5/24 brd 192.168.1.255 scope global dynamic noprefixroute wlp2s0
valid_lft 253560sec preferred_lft 253560sec
inet6 fe80::6324:f2f6:2c32:5ac8/64 scope link noprefixroute
valid_lft forever preferred_lft forever
$echo $?
0
$echo $eval
$eval pw d
bash: pw: command not found
$eval
[/bash]
LINK
https://www.computerhope.com/unix/bash/eval.htm
valavil.in 