Sstrhsrtj

i want to print interface names only from iwconfig command

this is output of iwconfig:

wlp2s0    IEEE 802.11  ESSID:"CoreFragment"  

          Mode:Managed  Frequency:2.442 GHz  Access Point: 0C:D2:B5:55:DF:74   

          Bit Rate=72.2 Mb/s   Tx-Power=22 dBm   

          Retry short limit:7   RTS thr:off   Fragment thr:off

          Power Management:on

          Link Quality=55/70  Signal level=-55 dBm  

          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0

          Tx excessive retries:4  Invalid misc:6567   Missed beacon:0



enp3s0    no wireless extensions.



wlx00e02d01076f  IEEE 802.11bgn  ESSID:"Aleph_inCar"  Nickname:"<WIFI@REALTEK>"

          Mode:Master  Frequency:2.412 GHz  Access Point: 00:E0:2D:01:07:6F   

          Bit Rate:72.2 Mb/s   Sensitivity:0/0  

          Retry:off   RTS thr:off   Fragment thr:off

          Power Management:off

          Link Quality=4/100  Signal level=4/100  Noise level=0/100

          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0

          Tx excessive retries:0  Invalid misc:0   Missed beacon:0



lo        no wireless extensions.



enx001e101f0000  no wireless extensions.  

I tried this :

iwconfig | grep ESSID | sed 's/"//g' | cut -f1  -d" "    

but i got no wireless extension also in output

i want to get output from iwconfig command only

how print wlp2s0,enp3s0,wlx00e02d01076f,enx001e101f0000 only...

Your command works perfectly. Simply redirect the STDERR output to STDOUT, so that grep and cut process them as you want:

iwconfig 2>&1 | grep ESSID | sed 's/"//g' | cut -f1  -d" "  

However, this method using grep, sed and cut is an overkill. A single grep can get you what you want as suggested in the update below.

UDPATE:

As per the edited question, and given that the user is using Ubuntu (and hence the grep supports Perl regex), here is one method:

iwconfig 2>&1 | grep -oP "^w+"