$ tree
.
├── Original_folder
│   └── cat.txt
├── folderCD
│   └── cat.txt
├── folderGK
│   └── cat.txt
├── folderFE
    └── cat.txt

Version LRv1.10.0
Build date 2017-12-06
MOL-calc
PRESSURE
!
      Time[s]     InletT[K]   InletP[Pa]   O2_GasOut     C_GasOut
       100         0.000885   1000000       0.0007       0.2111
and so on....

#!/bin/bash

gawk -F $'t' '                                     # Using TABs as field separators
   /_GasOut/{                                       # On lines containing "_GasOut"
      for(f=1;f<=NF;f++){                           # ... iterate over all fields on line
         this=$f                                    # ... picking them up
         if(index(this,"_GasOut"))wanted[f]=1       # ... and noting which ones we want to print
      }
   }
   ENDFILE{                                         # As we reaach end of each file
      for(f in wanted){                             # ... iterate over wanted fields
         if(length(cmds)) cmds = cmds ",n"         # ... adding commas and newlines if needed
         cmds = cmds """ FILENAME "" using 1:" f  # ... and adding the "using" statement
      }
      delete wanted                                 # Forget list of wanted fields for next file
   }
   END{                                             # At very end of last file
      print cmds                                    # ... print accumulated gnuplot cmds
   }

   ' folder*/cat.txt

(Original_folder)
"Original_folder/cat.txt" using 1:22,
"Original_folder/cat.txt" using 1:23,
"Original_folder/cat.txt" using 1:24,
"Original_folder/cat.txt" using 1:25,
"Original_folder/cat.txt" using 1:26,
"Original_folder/cat.txt" using 1:27,
"Original_folder/cat.txt" using 1:28,

(Other folders)
"folderCD/cat.txt" using 1:22,
"folderCD/cat.txt" using 1:23,
"folderCD/cat.txt" using 1:24,
"folderCD/cat.txt" using 1:25,
"folderCD/cat.txt" using 1:26,
"folderCD/cat.txt" using 1:27,
"folderCD/cat.txt" using 1:28,
"folderGK/cat.txt" using 1:22,
"folderGK/cat.txt" using 1:23,
"folderGK/cat.txt" using 1:24,
"folderGK/cat.txt" using 1:25,
"folderGK/cat.txt" using 1:26,
"folderGK/cat.txt" using 1:27,
"folderGK/cat.txt" using 1:28

gnuplot>plot "Original_folder/cat.txt" using 1:22,
             "folderCD/cat.txt" using 1:22