cat << 'END'
//UPLOAD  JOB (TSO),
//             'Upload Text',
//             CLASS=A,
//             MSGCLASS=A,
//             MSGLEVEL=(1,1),
//             USER=IBMUSER,
//             PASSWORD=SYS1
/*JOBPARM   LINES=1000
//*
//*  Creates MY.PDS.LOCATION
//*  Adds all txt files from ./folder
//*
//NJE38MAC EXEC PGM=PDSLOAD
//* Uncomment this line if using MVS/CE
//*STEPLIB  DD  DSN=SYSC.LINKLIB,DISP=SHR
//SYSPRINT DD  SYSOUT=*
//SYSUT2   DD  DSN=MY.PDS.LOCATION,DISP=(NEW,CATLG),
//             VOL=SER=PUB001,
//             UNIT=3390,SPACE=(CYL,(1,1,5)),
//             DCB=(BLKSIZE=3120,RECFM=FB,LRECL=80)
//SYSUT1   DD  DATA,DLM=@@
END

for i in folder/*.txt;do
    filename=$(basename -- "$i")
    echo "./ ADD NAME=${filename%.*}"
    cat $i
done
echo "@@“


cat << 'END'
//UPLOAD  JOB (TSO),
//             'Upload Text',
//             CLASS=A,
//             MSGCLASS=A,
//             MSGLEVEL=(1,1),
//             USER=IBMUSER,
//             PASSWORD=SYS1
/*JOBPARM   LINES=1000
//*
//*  Creates MY.PDS.LOCATION
//*  Adds all txt files from ./folder
//*
//NJE38MAC EXEC PGM=PDSLOAD
//* Uncomment this line if using MVS/CE
//*STEPLIB  DD  DSN=SYSC.LINKLIB,DISP=SHR
//SYSPRINT DD  SYSOUT=*
//SYSUT2   DD  DSN=MY.PDS.LOCATION,DISP=SHR
//SYSUT1   DD  DATA,DLM=@@
END

for i in folder/*.txt;do
    filename=$(basename -- "$i")
    echo "./ ADD NAME=${filename%.*}"
    cat $i
done
echo "@@“

typically i'll use bash script.name.sh | ncat localhost 3505


typically i'll use bash script.name.sh | ncat localhost 3505

Something like this should work, point it at the root folder, for example if i have /home/mf/jobs/hts0314.job.nmvs.cntl it would run this script like bash build_jcl.sh /home/mf/jobs
if [ -z "$1" ]; then
    base_folder='./'
else
    base_folder=$1
fi


cat << 'END'
//UPLOAD  JOB (TSO),
//             'Upload Text',
//             CLASS=A,
//             MSGCLASS=A,
//             MSGLEVEL=(1,1),
//             USER=IBMUSER,
//             PASSWORD=SYS1
/*JOBPARM   LINES=1000
END

STEP=1
for folder in $(find $base_folder -mindepth 1 -type d -printf '%P\n'); do 

cat << END
//*
//*  Creating ${folder^^}
//*  Adding all files from:
//*  $base_folder/$folder
//*
//STEP$STEP EXEC PGM=PDSLOAD
//* Uncomment this line if using MVS/CE
//*STEPLIB  DD  DSN=SYSC.LINKLIB,DISP=SHR
//SYSPRINT DD  SYSOUT=*
//SYSUT2   DD  DSN=${folder^^},DISP=(NEW,CATLG),
//             VOL=SER=PUB001,
//             UNIT=3390,SPACE=(CYL,(1,1,5)),
//             DCB=(BLKSIZE=3120,RECFM=FB,LRECL=80)
//SYSUT1   DD  DATA,DLM=@#
END

    for i in $folder/*;do
        filename=$(basename -- "$i")
        echo "./ ADD NAME=${filename%.*}"
        cat $i
    done
    echo '' # this is incase any of the files dont end on a newline
    echo "@#"
    STEP=$((STEP+1))
done